My Health Record FHIR IG
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My Health Record FHIR IG - Local Development build (v1.2.0) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

Resource Profile: MHRObservationMCV - Detailed Descriptions

Active as of 2024-09-19

Definitions for the dh-observation-mcv-1 resource profile.

Guidance on how to interpret the contents of this table can be found here

0. Observation
2. Observation.id
Control1..?
4. Observation.status
Must Supporttrue
Obligations
    ObligationsActor
    SHALL:handleMHR Gateway Requester
    Fixed Valuefinal
    6. Observation.category
    Control1..1
    Must Supporttrue
    Obligations
      ObligationsActor
      SHALL:handleMHR Gateway Requester
      8. Observation.code
      Must Supporttrue
      Obligations
        ObligationsActor
        SHALL:handleMHR Gateway Requester
        10. Observation.subject
        Control1..?
        TypeReference(MHR Patient)
        Must Supporttrue
        Obligations
          ObligationsActor
          SHALL:handleMHR Gateway Requester
          12. Observation.effective[x]
          TypedateTime, Period, Timing, instant
          [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supporttrue
          Obligations
            ObligationsActor
            SHALL:handleMHR Gateway Requester
            14. Observation.note
            Control0..1
            Must Supporttrue
            Obligations
              ObligationsActor
              SHALL:handleMHR Gateway Requester

              Guidance on how to interpret the contents of this table can be found here

              0. Observation
              Definition

              Measurements and simple assertions made about a patient, device or other subject.

              ShortMeasurements and simple assertions
              Comments

              Used for simple observations such as device measurements, laboratory atomic results, vital signs, height, weight, smoking status, comments, etc. Other resources are used to provide context for observations such as laboratory reports, etc.

              Control0..*
              Is Modifierfalse
              Summaryfalse
              Alternate NamesVital Signs, Measurement, Results, Tests
              Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
              dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
              dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
              dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
              dom-6: A resource should have narrative for robust management (text.`div`.exists())
              obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (dataAbsentReason.empty() or value.empty())
              obs-7: If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present (value.empty() or component.code.where(coding.intersect(%resource.code.coding).exists()).empty())
              obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (dataAbsentReason.empty() or value.empty())
              obs-7: If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present (value.empty() or component.code.where(coding.intersect(%resource.code.coding).exists()).empty())
              2. Observation.id
              Definition

              The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

              ShortLogical id of this artifact
              Comments

              The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

              Control10..1
              Typeidstring
              Is Modifierfalse
              Summarytrue
              4. Observation.implicitRules
              Definition

              A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

              ShortA set of rules under which this content was created
              Comments

              Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

              Control0..1
              Typeuri
              Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
              Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
              Summarytrue
              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              6. Observation.modifierExtension
              Definition

              May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

              Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

              ShortExtensions that cannot be ignored
              Comments

              There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

              Control0..*
              TypeExtension
              Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
              Summaryfalse
              Requirements

              Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

              Alternate Namesextensions, user content
              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
              8. Observation.status
              Definition

              The status of the result value.

              Shortregistered | preliminary | final | amended +
              Comments

              This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

              Control1..1
              BindingThe codes SHALL be taken from ObservationStatushttp://hl7.org/fhir/ValueSet/observation-status|4.0.1
              (required to http://hl7.org/fhir/ValueSet/observation-status|4.0.1)

              Codes providing the status of an observation.

              Typecode
              Is Modifiertrue because This element is labeled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
              Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
              Must Supporttrue
              Obligations
                ObligationsActor
                SHALL:handleMHR Gateway Requester
                Summarytrue
                Requirements

                Need to track the status of individual results. Some results are finalized before the whole report is finalized.

                Fixed Valuefinal
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                10. Observation.category
                Definition

                A code that classifies the general type of observation being made.

                ShortClassification of type of observation
                Comments

                In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once. The level of granularity is defined by the category concepts in the value set.

                Control10..1*
                BindingThe codes SHOULD be taken from ObservationCategoryCodeshttp://hl7.org/fhir/ValueSet/observation-category
                (preferred to http://hl7.org/fhir/ValueSet/observation-category)

                Codes for high level observation categories.

                TypeCodeableConcept
                Is Modifierfalse
                Must Supporttrue
                Obligations
                  ObligationsActor
                  SHALL:handleMHR Gateway Requester
                  Summaryfalse
                  Requirements

                  Used for filtering what observations are retrieved and displayed.

                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  12. Observation.code
                  Definition

                  Describes what was observed. Sometimes this is called the observation "name".

                  ShortType of observation (code / type)
                  Comments

                  All code-value and, if present, component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

                  Control1..1
                  BindingFor example codes, see LOINCCodeshttp://hl7.org/fhir/ValueSet/observation-codes
                  (example to http://hl7.org/fhir/ValueSet/observation-codes)

                  Codes identifying names of simple observations.

                  TypeCodeableConcept
                  Is Modifierfalse
                  Must Supporttrue
                  Obligations
                    ObligationsActor
                    SHALL:handleMHR Gateway Requester
                    Summarytrue
                    Requirements

                    Knowing what kind of observation is being made is essential to understanding the observation.

                    Alternate NamesName
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    14. Observation.subject
                    Definition

                    The patient, or group of patients, location, or device this observation is about and into whose record the observation is placed. If the actual focus of the observation is different from the subject (or a sample of, part, or region of the subject), the focus element or the code itself specifies the actual focus of the observation.

                    ShortWho and/or what the observation is about
                    Comments

                    One would expect this element to be a cardinality of 1..1. The only circumstance in which the subject can be missing is when the observation is made by a device that does not know the patient. In this case, the observation SHALL be matched to a patient through some context/channel matching technique, and at this point, the observation should be updated.

                    Control10..1
                    TypeReference(MHR Patient, Patient, Group, Device, Location)
                    Is Modifierfalse
                    Must Supporttrue
                    Obligations
                      ObligationsActor
                      SHALL:handleMHR Gateway Requester
                      Summarytrue
                      Requirements

                      Observations have no value if you don't know who or what they're about.

                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                      16. Observation.effective[x]
                      Definition

                      The time or time-period the observed value is asserted as being true. For biological subjects - e.g. human patients - this is usually called the "physiologically relevant time". This is usually either the time of the procedure or of specimen collection, but very often the source of the date/time is not known, only the date/time itself.

                      ShortClinically relevant time/time-period for observation
                      Comments

                      At least a date should be present unless this observation is a historical report. For recording imprecise or "fuzzy" times (For example, a blood glucose measurement taken "after breakfast") use the Timing datatype which allow the measurement to be tied to regular life events.

                      Control0..1
                      TypedateTime, Period, Timing, instant
                      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                      Is Modifierfalse
                      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                      Must Supporttrue
                      Obligations
                        ObligationsActor
                        SHALL:handleMHR Gateway Requester
                        Summarytrue
                        Requirements

                        Knowing when an observation was deemed true is important to its relevance as well as determining trends.

                        Alternate NamesOccurrence
                        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                        18. Observation.note
                        Definition

                        Comments about the observation or the results.

                        ShortComments about the observation
                        Comments

                        May include general statements about the observation, or statements about significant, unexpected or unreliable results values, or information about its source when relevant to its interpretation.

                        Control0..1*
                        TypeAnnotation
                        Is Modifierfalse
                        Must Supporttrue
                        Obligations
                          ObligationsActor
                          SHALL:handleMHR Gateway Requester
                          Summaryfalse
                          Requirements

                          Need to be able to provide free text additional information.

                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))

                          Guidance on how to interpret the contents of this table can be found here

                          0. Observation
                          Definition

                          Measurements and simple assertions made about a patient, device or other subject.

                          ShortMeasurements and simple assertions
                          Comments

                          Used for simple observations such as device measurements, laboratory atomic results, vital signs, height, weight, smoking status, comments, etc. Other resources are used to provide context for observations such as laboratory reports, etc.

                          Control0..*
                          Is Modifierfalse
                          Summaryfalse
                          Alternate NamesVital Signs, Measurement, Results, Tests
                          Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
                          dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
                          dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
                          dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
                          dom-6: A resource should have narrative for robust management (text.`div`.exists())
                          obs-6: dataAbsentReason SHALL only be present if Observation.value[x] is not present (dataAbsentReason.empty() or value.empty())
                          obs-7: If Observation.code is the same as an Observation.component.code then the value element associated with the code SHALL NOT be present (value.empty() or component.code.where(coding.intersect(%resource.code.coding).exists()).empty())
                          2. Observation.id
                          Definition

                          The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

                          ShortLogical id of this artifact
                          Comments

                          The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

                          Control1..1
                          Typeid
                          Is Modifierfalse
                          Summarytrue
                          4. Observation.meta
                          Definition

                          The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

                          ShortMetadata about the resource
                          Control0..1
                          TypeMeta
                          Is Modifierfalse
                          Summarytrue
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          6. Observation.implicitRules
                          Definition

                          A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

                          ShortA set of rules under which this content was created
                          Comments

                          Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

                          Control0..1
                          Typeuri
                          Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
                          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                          Summarytrue
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          8. Observation.language
                          Definition

                          The base language in which the resource is written.

                          ShortLanguage of the resource content
                          Comments

                          Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

                          Control0..1
                          BindingThe codes SHOULD be taken from CommonLanguages
                          (preferred to http://hl7.org/fhir/ValueSet/languages)

                          A human language.

                          Additional BindingsPurpose
                          AllLanguagesMax Binding
                          Typecode
                          Is Modifierfalse
                          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                          Summaryfalse
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          10. Observation.text
                          Definition

                          A human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

                          ShortText summary of the resource, for human interpretation
                          Comments

                          Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

                          Control0..1
                          TypeNarrative
                          Is Modifierfalse
                          Summaryfalse
                          Alternate Namesnarrative, html, xhtml, display
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          12. Observation.contained
                          Definition

                          These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

                          ShortContained, inline Resources
                          Comments

                          This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

                          Control0..*
                          TypeResource
                          Is Modifierfalse
                          Summaryfalse
                          Alternate Namesinline resources, anonymous resources, contained resources
                          14. Observation.extension
                          Definition

                          May be used to represent additional information that is not part of the basic definition of the resource. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                          ShortAdditional content defined by implementations
                          Comments

                          There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                          Control0..*
                          TypeExtension
                          Is Modifierfalse
                          Summaryfalse
                          Alternate Namesextensions, user content
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                          16. Observation.modifierExtension
                          Definition

                          May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

                          Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

                          ShortExtensions that cannot be ignored
                          Comments

                          There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                          Control0..*
                          TypeExtension
                          Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
                          Summaryfalse
                          Requirements

                          Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

                          Alternate Namesextensions, user content
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                          18. Observation.identifier
                          Definition

                          A unique identifier assigned to this observation.

                          ShortBusiness Identifier for observation
                          NoteThis is a business identifier, not a resource identifier (see discussion)
                          Control0..*
                          TypeIdentifier
                          Is Modifierfalse
                          Summarytrue
                          Requirements

                          Allows observations to be distinguished and referenced.

                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          20. Observation.basedOn
                          Definition

                          A plan, proposal or order that is fulfilled in whole or in part by this event. For example, a MedicationRequest may require a patient to have laboratory test performed before it is dispensed.

                          ShortFulfills plan, proposal or order
                          Control0..*
                          TypeReference(CarePlan, DeviceRequest, ImmunizationRecommendation, MedicationRequest, NutritionOrder, ServiceRequest)
                          Is Modifierfalse
                          Summarytrue
                          Requirements

                          Allows tracing of authorization for the event and tracking whether proposals/recommendations were acted upon.

                          Alternate NamesFulfills
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          22. Observation.partOf
                          Definition

                          A larger event of which this particular Observation is a component or step. For example, an observation as part of a procedure.

                          ShortPart of referenced event
                          Comments

                          To link an Observation to an Encounter use encounter. See the Notes below for guidance on referencing another Observation.

                          Control0..*
                          TypeReference(MedicationAdministration, MedicationDispense, MedicationStatement, Procedure, Immunization, ImagingStudy)
                          Is Modifierfalse
                          Summarytrue
                          Alternate NamesContainer
                          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                          24. Observation.status
                          Definition

                          The status of the result value.

                          Shortregistered | preliminary | final | amended +
                          Comments

                          This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

                          Control1..1
                          BindingThe codes SHALL be taken from ObservationStatus
                          (required to http://hl7.org/fhir/ValueSet/observation-status|4.0.1)

                          Codes providing the status of an observation.

                          Typecode
                          Is Modifiertrue because This element is labeled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
                          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                          Must Supporttrue
                          Obligations
                            ObligationsActor
                            SHALL:handleMHR Gateway Requester
                            Summarytrue
                            Requirements

                            Need to track the status of individual results. Some results are finalized before the whole report is finalized.

                            Fixed Valuefinal
                            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                            26. Observation.category
                            Definition

                            A code that classifies the general type of observation being made.

                            ShortClassification of type of observation
                            Comments

                            In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once. The level of granularity is defined by the category concepts in the value set.

                            Control1..1
                            BindingThe codes SHOULD be taken from ObservationCategoryCodes
                            (preferred to http://hl7.org/fhir/ValueSet/observation-category)

                            Codes for high level observation categories.

                            TypeCodeableConcept
                            Is Modifierfalse
                            Must Supporttrue
                            Obligations
                              ObligationsActor
                              SHALL:handleMHR Gateway Requester
                              Summaryfalse
                              Requirements

                              Used for filtering what observations are retrieved and displayed.

                              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                              28. Observation.code
                              Definition

                              Describes what was observed. Sometimes this is called the observation "name".

                              ShortType of observation (code / type)
                              Comments

                              All code-value and, if present, component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

                              Control1..1
                              BindingFor example codes, see LOINCCodes
                              (example to http://hl7.org/fhir/ValueSet/observation-codes)

                              Codes identifying names of simple observations.

                              TypeCodeableConcept
                              Is Modifierfalse
                              Must Supporttrue
                              Obligations
                                ObligationsActor
                                SHALL:handleMHR Gateway Requester
                                Summarytrue
                                Requirements

                                Knowing what kind of observation is being made is essential to understanding the observation.

                                Alternate NamesName
                                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                30. Observation.subject
                                Definition

                                The patient, or group of patients, location, or device this observation is about and into whose record the observation is placed. If the actual focus of the observation is different from the subject (or a sample of, part, or region of the subject), the focus element or the code itself specifies the actual focus of the observation.

                                ShortWho and/or what the observation is about
                                Comments

                                One would expect this element to be a cardinality of 1..1. The only circumstance in which the subject can be missing is when the observation is made by a device that does not know the patient. In this case, the observation SHALL be matched to a patient through some context/channel matching technique, and at this point, the observation should be updated.

                                Control1..1
                                TypeReference(MHR Patient)
                                Is Modifierfalse
                                Must Supporttrue
                                Obligations
                                  ObligationsActor
                                  SHALL:handleMHR Gateway Requester
                                  Summarytrue
                                  Requirements

                                  Observations have no value if you don't know who or what they're about.

                                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                  32. Observation.focus
                                  Definition

                                  The actual focus of an observation when it is not the patient of record representing something or someone associated with the patient such as a spouse, parent, fetus, or donor. For example, fetus observations in a mother's record. The focus of an observation could also be an existing condition, an intervention, the subject's diet, another observation of the subject, or a body structure such as tumor or implanted device. An example use case would be using the Observation resource to capture whether the mother is trained to change her child's tracheostomy tube. In this example, the child is the patient of record and the mother is the focus.

                                  ShortWhat the observation is about, when it is not about the subject of record
                                  Comments

                                  Typically, an observation is made about the subject - a patient, or group of patients, location, or device - and the distinction between the subject and what is directly measured for an observation is specified in the observation code itself ( e.g., "Blood Glucose") and does not need to be represented separately using this element. Use specimen if a reference to a specimen is required. If a code is required instead of a resource use either bodysite for bodysites or the standard extension focusCode.

                                  Control0..*
                                  TypeReference(Resource)
                                  Is Modifierfalse
                                  Summarytrue
                                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                  34. Observation.encounter
                                  Definition

                                  The healthcare event (e.g. a patient and healthcare provider interaction) during which this observation is made.

                                  ShortHealthcare event during which this observation is made
                                  Comments

                                  This will typically be the encounter the event occurred within, but some events may be initiated prior to or after the official completion of an encounter but still be tied to the context of the encounter (e.g. pre-admission laboratory tests).

                                  Control0..1
                                  TypeReference(Encounter)
                                  Is Modifierfalse
                                  Summarytrue
                                  Requirements

                                  For some observations it may be important to know the link between an observation and a particular encounter.

                                  Alternate NamesContext
                                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                  36. Observation.effective[x]
                                  Definition

                                  The time or time-period the observed value is asserted as being true. For biological subjects - e.g. human patients - this is usually called the "physiologically relevant time". This is usually either the time of the procedure or of specimen collection, but very often the source of the date/time is not known, only the date/time itself.

                                  ShortClinically relevant time/time-period for observation
                                  Comments

                                  At least a date should be present unless this observation is a historical report. For recording imprecise or "fuzzy" times (For example, a blood glucose measurement taken "after breakfast") use the Timing datatype which allow the measurement to be tied to regular life events.

                                  Control0..1
                                  TypedateTime
                                  [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                                  Is Modifierfalse
                                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                                  Must Supporttrue
                                  Obligations
                                    ObligationsActor
                                    SHALL:handleMHR Gateway Requester
                                    Summarytrue
                                    Requirements

                                    Knowing when an observation was deemed true is important to its relevance as well as determining trends.

                                    Alternate NamesOccurrence
                                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                    38. Observation.issued
                                    Definition

                                    The date and time this version of the observation was made available to providers, typically after the results have been reviewed and verified.

                                    ShortDate/Time this version was made available
                                    Comments

                                    For Observations that don’t require review and verification, it may be the same as the lastUpdated time of the resource itself. For Observations that do require review and verification for certain updates, it might not be the same as the lastUpdated time of the resource itself due to a non-clinically significant update that doesn’t require the new version to be reviewed and verified again.

                                    Control0..1
                                    Typeinstant
                                    Is Modifierfalse
                                    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                                    Summarytrue
                                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                    40. Observation.performer
                                    Definition

                                    Who was responsible for asserting the observed value as "true".

                                    ShortWho is responsible for the observation
                                    Control0..*
                                    TypeReference(Practitioner, PractitionerRole, Organization, CareTeam, Patient, RelatedPerson)
                                    Is Modifierfalse
                                    Summarytrue
                                    Requirements

                                    May give a degree of confidence in the observation and also indicates where follow-up questions should be directed.

                                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                    42. Observation.value[x]
                                    Definition

                                    The information determined as a result of making the observation, if the information has a simple value.

                                    ShortActual result
                                    Comments

                                    An observation may have; 1) a single value here, 2) both a value and a set of related or component values, or 3) only a set of related or component values. If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

                                    Control0..1
                                    This element is affected by the following invariants: obs-7
                                    TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
                                    [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                                    Is Modifierfalse
                                    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                                    Summarytrue
                                    Requirements

                                    An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

                                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                    44. Observation.dataAbsentReason
                                    Definition

                                    Provides a reason why the expected value in the element Observation.value[x] is missing.

                                    ShortWhy the result is missing
                                    Comments

                                    Null or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "specimen unsatisfactory".

                                    The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Note that an observation may only be reported if there are values to report. For example differential cell counts values may be reported only when > 0. Because of these options, use-case agreements are required to interpret general observations for null or exceptional values.

                                    Control0..1
                                    This element is affected by the following invariants: obs-6
                                    BindingUnless not suitable, these codes SHALL be taken from DataAbsentReason
                                    (extensible to http://hl7.org/fhir/ValueSet/data-absent-reason)

                                    Codes specifying why the result (Observation.value[x]) is missing.

                                    TypeCodeableConcept
                                    Is Modifierfalse
                                    Summaryfalse
                                    Requirements

                                    For many results it is necessary to handle exceptional values in measurements.

                                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                    46. Observation.interpretation
                                    Definition

                                    A categorical assessment of an observation value. For example, high, low, normal.

                                    ShortHigh, low, normal, etc.
                                    Comments

                                    Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

                                    Control0..*
                                    BindingUnless not suitable, these codes SHALL be taken from ObservationInterpretationCodes
                                    (extensible to http://hl7.org/fhir/ValueSet/observation-interpretation)

                                    Codes identifying interpretations of observations.

                                    TypeCodeableConcept
                                    Is Modifierfalse
                                    Summaryfalse
                                    Requirements

                                    For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

                                    Alternate NamesAbnormal Flag
                                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                    48. Observation.note
                                    Definition

                                    Comments about the observation or the results.

                                    ShortComments about the observation
                                    Comments

                                    May include general statements about the observation, or statements about significant, unexpected or unreliable results values, or information about its source when relevant to its interpretation.

                                    Control0..1
                                    TypeAnnotation
                                    Is Modifierfalse
                                    Must Supporttrue
                                    Obligations
                                      ObligationsActor
                                      SHALL:handleMHR Gateway Requester
                                      Summaryfalse
                                      Requirements

                                      Need to be able to provide free text additional information.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      50. Observation.bodySite
                                      Definition

                                      Indicates the site on the subject's body where the observation was made (i.e. the target site).

                                      ShortObserved body part
                                      Comments

                                      Only used if not implicit in code found in Observation.code. In many systems, this may be represented as a related observation instead of an inline component.

                                      If the use case requires BodySite to be handled as a separate resource (e.g. to identify and track separately) then use the standard extension bodySite.

                                      Control0..1
                                      BindingFor example codes, see SNOMEDCTBodyStructures
                                      (example to http://hl7.org/fhir/ValueSet/body-site)

                                      Codes describing anatomical locations. May include laterality.

                                      TypeCodeableConcept
                                      Is Modifierfalse
                                      Summaryfalse
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      52. Observation.method
                                      Definition

                                      Indicates the mechanism used to perform the observation.

                                      ShortHow it was done
                                      Comments

                                      Only used if not implicit in code for Observation.code.

                                      Control0..1
                                      BindingFor example codes, see ObservationMethods
                                      (example to http://hl7.org/fhir/ValueSet/observation-methods)

                                      Methods for simple observations.

                                      TypeCodeableConcept
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      In some cases, method can impact results and is thus used for determining whether results can be compared or determining significance of results.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      54. Observation.specimen
                                      Definition

                                      The specimen that was used when this observation was made.

                                      ShortSpecimen used for this observation
                                      Comments

                                      Should only be used if not implicit in code found in Observation.code. Observations are not made on specimens themselves; they are made on a subject, but in many cases by the means of a specimen. Note that although specimens are often involved, they are not always tracked and reported explicitly. Also note that observation resources may be used in contexts that track the specimen explicitly (e.g. Diagnostic Report).

                                      Control0..1
                                      TypeReference(Specimen)
                                      Is Modifierfalse
                                      Summaryfalse
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      56. Observation.device
                                      Definition

                                      The device used to generate the observation data.

                                      Short(Measurement) Device
                                      Comments

                                      Note that this is not meant to represent a device involved in the transmission of the result, e.g., a gateway. Such devices may be documented using the Provenance resource where relevant.

                                      Control0..1
                                      TypeReference(Device, DeviceMetric)
                                      Is Modifierfalse
                                      Summaryfalse
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      58. Observation.referenceRange
                                      Definition

                                      Guidance on how to interpret the value by comparison to a normal or recommended range. Multiple reference ranges are interpreted as an "OR". In other words, to represent two distinct target populations, two referenceRange elements would be used.

                                      ShortProvides guide for interpretation
                                      Comments

                                      Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

                                      Control0..*
                                      TypeBackboneElement
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      obs-3: Must have at least a low or a high or text (low.exists() or high.exists() or text.exists())
                                      60. Observation.referenceRange.id
                                      Definition

                                      Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                                      ShortUnique id for inter-element referencing
                                      Control0..1
                                      Typestring
                                      Is Modifierfalse
                                      XML FormatIn the XML format, this property is represented as an attribute.
                                      Summaryfalse
                                      62. Observation.referenceRange.extension
                                      Definition

                                      May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                                      ShortAdditional content defined by implementations
                                      Comments

                                      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                                      Control0..*
                                      TypeExtension
                                      Is Modifierfalse
                                      Summaryfalse
                                      Alternate Namesextensions, user content
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                                      64. Observation.referenceRange.modifierExtension
                                      Definition

                                      May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

                                      Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

                                      ShortExtensions that cannot be ignored even if unrecognized
                                      Comments

                                      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                                      Control0..*
                                      TypeExtension
                                      Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
                                      Summarytrue
                                      Requirements

                                      Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

                                      Alternate Namesextensions, user content, modifiers
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                                      66. Observation.referenceRange.low
                                      Definition

                                      The value of the low bound of the reference range. The low bound of the reference range endpoint is inclusive of the value (e.g. reference range is >=5 - <=9). If the low bound is omitted, it is assumed to be meaningless (e.g. reference range is <=2.3).

                                      ShortLow Range, if relevant
                                      Control0..1
                                      This element is affected by the following invariants: obs-3
                                      TypeQuantity(SimpleQuantity)
                                      Is Modifierfalse
                                      Summaryfalse
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      68. Observation.referenceRange.high
                                      Definition

                                      The value of the high bound of the reference range. The high bound of the reference range endpoint is inclusive of the value (e.g. reference range is >=5 - <=9). If the high bound is omitted, it is assumed to be meaningless (e.g. reference range is >= 2.3).

                                      ShortHigh Range, if relevant
                                      Control0..1
                                      This element is affected by the following invariants: obs-3
                                      TypeQuantity(SimpleQuantity)
                                      Is Modifierfalse
                                      Summaryfalse
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      70. Observation.referenceRange.type
                                      Definition

                                      Codes to indicate the what part of the targeted reference population it applies to. For example, the normal or therapeutic range.

                                      ShortReference range qualifier
                                      Comments

                                      This SHOULD be populated if there is more than one range. If this element is not present then the normal range is assumed.

                                      Control0..1
                                      BindingThe codes SHOULD be taken from ObservationReferenceRangeMeaningCodes
                                      (preferred to http://hl7.org/fhir/ValueSet/referencerange-meaning)

                                      Code for the meaning of a reference range.

                                      TypeCodeableConcept
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      Need to be able to say what kind of reference range this is - normal, recommended, therapeutic, etc., - for proper interpretation.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      72. Observation.referenceRange.appliesTo
                                      Definition

                                      Codes to indicate the target population this reference range applies to. For example, a reference range may be based on the normal population or a particular sex or race. Multiple appliesTo are interpreted as an "AND" of the target populations. For example, to represent a target population of African American females, both a code of female and a code for African American would be used.

                                      ShortReference range population
                                      Comments

                                      This SHOULD be populated if there is more than one range. If this element is not present then the normal population is assumed.

                                      Control0..*
                                      BindingFor example codes, see ObservationReferenceRangeAppliesToCodes
                                      (example to http://hl7.org/fhir/ValueSet/referencerange-appliesto)

                                      Codes identifying the population the reference range applies to.

                                      TypeCodeableConcept
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      Need to be able to identify the target population for proper interpretation.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      74. Observation.referenceRange.age
                                      Definition

                                      The age at which this reference range is applicable. This is a neonatal age (e.g. number of weeks at term) if the meaning says so.

                                      ShortApplicable age range, if relevant
                                      Control0..1
                                      TypeRange
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      Some analytes vary greatly over age.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      76. Observation.referenceRange.text
                                      Definition

                                      Text based reference range in an observation which may be used when a quantitative range is not appropriate for an observation. An example would be a reference value of "Negative" or a list or table of "normals".

                                      ShortText based reference range in an observation
                                      Control0..1
                                      Typestring
                                      Is Modifierfalse
                                      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                                      Summaryfalse
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      78. Observation.hasMember
                                      Definition

                                      This observation is a group observation (e.g. a battery, a panel of tests, a set of vital sign measurements) that includes the target as a member of the group.

                                      ShortRelated resource that belongs to the Observation group
                                      Comments

                                      When using this element, an observation will typically have either a value or a set of related resources, although both may be present in some cases. For a discussion on the ways Observations can assembled in groups together, see Notes below. Note that a system may calculate results from QuestionnaireResponse into a final score and represent the score as an Observation.

                                      Control0..*
                                      TypeReference(Observation, QuestionnaireResponse, MolecularSequence)
                                      Is Modifierfalse
                                      Summarytrue
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      80. Observation.derivedFrom
                                      Definition

                                      The target resource that represents a measurement from which this observation value is derived. For example, a calculated anion gap or a fetal measurement based on an ultrasound image.

                                      ShortRelated measurements the observation is made from
                                      Comments

                                      All the reference choices that are listed in this element can represent clinical observations and other measurements that may be the source for a derived value. The most common reference will be another Observation. For a discussion on the ways Observations can assembled in groups together, see Notes below.

                                      Control0..*
                                      TypeReference(DocumentReference, ImagingStudy, Media, QuestionnaireResponse, Observation, MolecularSequence)
                                      Is Modifierfalse
                                      Summarytrue
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      82. Observation.component
                                      Definition

                                      Some observations have multiple component observations. These component observations are expressed as separate code value pairs that share the same attributes. Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

                                      ShortComponent results
                                      Comments

                                      For a discussion on the ways Observations can be assembled in groups together see Notes below.

                                      Control0..*
                                      TypeBackboneElement
                                      Is Modifierfalse
                                      Summarytrue
                                      Requirements

                                      Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable). However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      84. Observation.component.id
                                      Definition

                                      Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

                                      ShortUnique id for inter-element referencing
                                      Control0..1
                                      Typestring
                                      Is Modifierfalse
                                      XML FormatIn the XML format, this property is represented as an attribute.
                                      Summaryfalse
                                      86. Observation.component.extension
                                      Definition

                                      May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

                                      ShortAdditional content defined by implementations
                                      Comments

                                      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                                      Control0..*
                                      TypeExtension
                                      Is Modifierfalse
                                      Summaryfalse
                                      Alternate Namesextensions, user content
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                                      88. Observation.component.modifierExtension
                                      Definition

                                      May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

                                      Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

                                      ShortExtensions that cannot be ignored even if unrecognized
                                      Comments

                                      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

                                      Control0..*
                                      TypeExtension
                                      Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
                                      Summarytrue
                                      Requirements

                                      Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

                                      Alternate Namesextensions, user content, modifiers
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
                                      90. Observation.component.code
                                      Definition

                                      Describes what was observed. Sometimes this is called the observation "code".

                                      ShortType of component observation (code / type)
                                      Comments

                                      All code-value and component.code-component.value pairs need to be taken into account to correctly understand the meaning of the observation.

                                      Control1..1
                                      BindingFor example codes, see LOINCCodes
                                      (example to http://hl7.org/fhir/ValueSet/observation-codes)

                                      Codes identifying names of simple observations.

                                      TypeCodeableConcept
                                      Is Modifierfalse
                                      Summarytrue
                                      Requirements

                                      Knowing what kind of observation is being made is essential to understanding the observation.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      92. Observation.component.value[x]
                                      Definition

                                      The information determined as a result of making the observation, if the information has a simple value.

                                      ShortActual component result
                                      Comments

                                      Used when observation has a set of component observations. An observation may have both a value (e.g. an Apgar score) and component observations (the observations from which the Apgar score was derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value. For additional guidance, see the Notes section below.

                                      Control0..1
                                      TypeChoice of: Quantity, CodeableConcept, string, boolean, integer, Range, Ratio, SampledData, time, dateTime, Period
                                      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                                      Is Modifierfalse
                                      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                                      Summarytrue
                                      Requirements

                                      An observation exists to have a value, though it might not if it is in error, or if it represents a group of observations.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      94. Observation.component.dataAbsentReason
                                      Definition

                                      Provides a reason why the expected value in the element Observation.component.value[x] is missing.

                                      ShortWhy the component result is missing
                                      Comments

                                      "Null" or exceptional values can be represented two ways in FHIR Observations. One way is to simply include them in the value set and represent the exceptions in the value. For example, measurement values for a serology test could be "detected", "not detected", "inconclusive", or "test not done".

                                      The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values. For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Because of these options, use-case agreements are required to interpret general observations for exceptional values.

                                      Control0..1
                                      This element is affected by the following invariants: obs-6
                                      BindingUnless not suitable, these codes SHALL be taken from DataAbsentReason
                                      (extensible to http://hl7.org/fhir/ValueSet/data-absent-reason)

                                      Codes specifying why the result (Observation.value[x]) is missing.

                                      TypeCodeableConcept
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      For many results it is necessary to handle exceptional values in measurements.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      96. Observation.component.interpretation
                                      Definition

                                      A categorical assessment of an observation value. For example, high, low, normal.

                                      ShortHigh, low, normal, etc.
                                      Comments

                                      Historically used for laboratory results (known as 'abnormal flag' ), its use extends to other use cases where coded interpretations are relevant. Often reported as one or more simple compact codes this element is often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result.

                                      Control0..*
                                      BindingUnless not suitable, these codes SHALL be taken from ObservationInterpretationCodes
                                      (extensible to http://hl7.org/fhir/ValueSet/observation-interpretation)

                                      Codes identifying interpretations of observations.

                                      TypeCodeableConcept
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

                                      Alternate NamesAbnormal Flag
                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                                      98. Observation.component.referenceRange
                                      Definition

                                      Guidance on how to interpret the value by comparison to a normal or recommended range.

                                      ShortProvides guide for interpretation of component result
                                      Comments

                                      Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this might not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

                                      Control0..*
                                      TypeSeettp://hl7.org/fhir/StructureDefinition/Observation#Observation.referenceRange
                                      Is Modifierfalse
                                      Summaryfalse
                                      Requirements

                                      Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

                                      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))