NamingSystem — detail: system registry

Official declaration of an identifier system or code reference: French INS-NIR, English NHS Number, DICOM OIDs, SNOMED CT namespace.

Role in identifier qualification

Each Patient.identifier carries a system (canonical URL of the issuing authority) and a value. NamingSystem publishes the reference of all valid systems: who owns OID 1.2.250.1.213.1.4.8? What URL represents it? NamingSystem answers.

kind: codesystem | identifier | root

• codesystem — describes a code system (SNOMED CT, LOINC).
• identifier — describes an identifier system (INS-NIR, NHS Number, NPI, BSN).
• root — hierarchical OID root (1.2.250.1 for France health).

uniqueId: OID, UUID, URI, URL, v2csmnemonic, other

A NamingSystem can publish several equivalent identifiers. The preferred flag marks the canonical one. Example for INS-NIR:

• type=oid, value=1.2.250.1.213.1.4.8, preferred=true.
• type=uri, value=urn:oid:1.2.250.1.213.1.4.8.

Example: INS-NIR

{
  "resourceType": "NamingSystem",
  "id": "ins-nir",
  "name": "FrenchINSNIR",
  "title": "Identifiant National de Sante - NIR",
  "status": "active",
  "kind": "identifier",
  "date": "2026-05-18",
  "publisher": "Agence du Numerique en Sante (ANS)",
  "responsible": "ANS",
  "type": {
    "coding": [{
      "system": "http://terminology.hl7.org/CodeSystem/v2-0203",
      "code": "NH",
      "display": "National unique individual identifier"
    }]
  },
  "description": "INS-NIR: French National Health Identifier derived from the social security number (NIR). Mandatory carrier in clinical exchanges since 2021.",
  "usage": "Carrier in Patient.identifier with use=official and assigner=Organization/cnam-ts",
  "jurisdiction": [{
    "coding": [{ "system": "urn:iso:std:iso:3166", "code": "FR" }]
  }],
  "uniqueId": [{
    "type": "oid",
    "value": "1.2.250.1.213.1.4.8",
    "preferred": true,
    "comment": "Official ANS OID"
  }, {
    "type": "uri",
    "value": "urn:oid:1.2.250.1.213.1.4.8"
  }]
}

Common pitfalls

• Multiple preferred — only one uniqueId may be marked preferred=true.
• OID without urn:oid: prefix — when declaring type=uri, always prefix.
• Inconsistent kind — declaring a NamingSystem kind=codesystem for a Patient identifier system is a semantic error.

Related resources

• NamingSystem — overview
• Patient
• CodeSystem
• ValueSet