Guideline Definition Language v2 (GDL2) vCDS 2.0.1

Two main challenges to sharing clinical decision support content across sites are the lack of commonly shared clinical information models and flexible support for various language resources.

This document contains the design specifications of the Guideline Definition Language version 2 (GDL2), which is a formal language for expressing decision support logic in openEHR systems. It expresses clinical logic as production rules, which can be combined to support decision-making processes. These rules can be used to drive at-point-of-care decision support as well as retrospective populational analytics.

This specification helps overcome challenges in sharing clinical decision support content by providing a commonly shared clinical information model and flexible support for various language resources. GDL2 can support prompts, alerts and reminders; interactive single-screen decision support applications; detailed order-sets and care process support; algorithm-based calculators and more.

GDL2 introduces the following changes from the original GDL release:

· Data binding agnostic to EHR data models (e.g. openEHR / ISO 13606 / HL7 FHIR)

· Template definition for output objects with new use_template statement with template-level variables; this enables, for example CDS-Hooks Cards & Suggestions as result of rule executions

· Individual references and ability to reference to specific items in the rules

· More math functions support.

Main sections:

· Overview

· Requirements

· GDL2 semantics

· GDL2 object model

· Syntax specification

· Amendment record