HL7 Terminology (THO)
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HL7 Terminology (THO), published by HL7 International - Vocabulary Work Group. This guide is not an authorized publication; it is the continuous build for version 7.2.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/UTG/ and changes regularly. See the Directory of published versions

CodeSystem: Evidence Variable Constraint

Official URL: http://terminology.hl7.org/CodeSystem/evidence-variable-constraint Version: 1.0.0
Active as of 2026-05-04 Maturity Level: 1 Responsible: HL7 (FHIR Project) Computable Name: EvidenceVariableConstraint

A rule or other expectation for data values.

This Code system is referenced in the definition of the following value sets:

This case-sensitive code system http://terminology.hl7.org/CodeSystem/evidence-variable-constraint defines the following codes:

CodeDisplayDefinition
alphanumeric-only Alphanumeric Characters Only String values that are restricted to only numbers and letters [A-Za-z0-9].
alphanumeric-space-only Alphanumeric and Space Characters Only String values that are restricted to only numbers, letters, and spaces [A-Za-z0-9\s].
range-zero-to-one Range Zero to One Numeric value between 0 and 1, inclusive.

Description of the above table(s).