Terminology Fundamentals, published by HL7 International / Terminology Infrastructure. This guide is not an authorized publication; it is the continuous build for version 0.1.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/terminology-fundamentals-ig/ and changes regularly. See the Directory of published versions

Examples

Page standards status: Informative

This page provides examples of Value Set content defined using an expression-based approach. These examples illustrate different patterns for defining Value Sets, including enumerated definitions, groupings, and intensional definitions based on hierarchical relationships and properties.

The goal of these examples is to demonstrate how expression-based Value Set definitions are used.

Total Colectomy Value Sets

The Total Colectomy Value Sets described in these examples are actual Value Sets used in the US electronic quality measure program. The Total Colectomy Grouping example and the three grouped Value Sets that make up the grouping: Total Colectomy CPT, Total Colectomy SNOMED CT, and Total Colectomy ICD-10-PCS, all exist in the US NLM Value Set Authority Center (VSAC).

The Total Colectomy Grouping example demonstrates how a single Value Set using VSAC's grouping syntax could be constructed using enumerated codes from multiple Code Systems.

RoleClass-based Value Sets

The RoleClassAssignedEntity Value Set uses the RoleClass Code System. This example demonstrates two things:

1. Both RoleClassAssignedEntity and RoleClassContact use an "intensional" definition style to identifying concepts to be included in the Expansion Code Set wherein a single code is provided along with a relationship traversal that clarifies that a transitive closure traversal is to be followed to find all codes related to the code provided. This is how "and all descendants" is communicated.
2. RoleClassAssignedEntity unions together the "code and all descendants" noted above plus a reference to another value set - RoleClassContact.

Urine Albumin Lab Test Value Sets

The Urine Albumin Lab Test Value Set in this example uses LOINC properties to create an expression to capture all LOINC codes that measure albumin in a urine specimen. The expression below was created using Apelon's Distributed Terminology System (DTS).

This expression uses an intensional definition, and when expanded includes the following codes: