← ReferenceTerminology

What is a ValueSet?

A ValueSet is a curated collection of codes selected from one or more CodeSystems. ValueSets are used in profiles to constrain what codes are valid for a specific element — for example, a list of allowed clinical status codes for a Condition, or the set of LOINC codes used for lab results in a given IG.

ValueSet vs CodeSystem

CodeSystem — defines codes and their meanings (SNOMED CT, LOINC, ICD-10 are CodeSystems)
ValueSet — selects a subset of codes from one or more CodeSystems for use in a specific context
A ValueSet does not define new codes — it references existing ones

ValueSet — condition clinical status codes

{
  "resourceType": "ValueSet",
  "id": "condition-clinical",
  "url": "http://terminology.hl7.org/ValueSet/condition-clinical",
  "name": "ConditionClinicalStatusCodes",
  "status": "active",
  "compose": {
    "include": [{
      "system": "http://terminology.hl7.org/CodeSystem/condition-clinical",
      "concept": [
        { "code": "active" },
        { "code": "recurrence" },
        { "code": "relapse" },
        { "code": "inactive" },
        { "code": "remission" },
        { "code": "resolved" }
      ]
    }]
  }
}

Binding strength

required: Must use a code from this ValueSet. Validation fails if not.
extensible: Prefer codes from this ValueSet. May use other codes if needed.
preferred: Use codes from this ValueSet if possible — not enforced.
example: Illustrative only — no validation constraint.