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The Terminology service answers FHIR R4 terminology operations (CodeSystem/$lookup, CodeSystem/$validate-code, ValueSet/$expand and ValueSet/$validate-code) about the code systems on this page. Each section says what the system is, who publishes it, the URI to send as system, the other names and OIDs a request may use for it, its licence, and whether it is served.

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LOINC

LOINC (Logical Observation Identifiers Names and Codes) identifies laboratory tests, clinical measurements and other observations, and the panels and survey instruments built from them. It is the default here: an operation that names no system, or no url, asks about LOINC.
  • Status: Served. Available to any caller with an API key.
  • URI: http://loinc.org
  • Also recognised as: LOINC, loinc, urn:oid:2.16.840.1.113883.6.1
  • Publisher: Regenstrief Institute
  • Licence: Free to use under LOINC’s licence. The notice is in the Terminology service page’s Legal section.
  • More: Look up a code

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RxNorm

RxNorm gives the clinical drugs available in the United States normalized names and codes (RxCUIs), and links them to the drug vocabularies used in pharmacy and drug interaction software.
  • Status: Served. Available to any caller with an API key. Held at a named release: GET /v1/fhir/r4/metadata?mode=terminology names the release being served, and a deployment with no release published yet answers 503.
  • URI: http://www.nlm.nih.gov/research/umls/rxnorm
  • Also recognised as: RXNORM, RxNorm, urn:oid:2.16.840.1.113883.6.88
  • Publisher: U.S. National Library of Medicine (NLM)
  • Licence: Publicly available from NLM. The notice is in the Terminology service page’s Legal section.
  • More: RxNorm on the Terminology service page: what we hold, and what a “no” means

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SNOMED CT

SNOMED CT is a clinical terminology for findings, disorders, procedures, body structures, organisms, substances and more, used in health records worldwide.
  • Status: Not served. SNOMED CT is free in the United States only through a UMLS Metathesaurus licence, and NLM does not permit a vendor to cover its customers under its own licence, so the terminology operations do not serve it. Callers holding their own UMLS credentials will be able to use them here.
  • URI: http://snomed.info/sct
  • Also recognised as: SNOMED, SNOMEDCT, SCT, urn:oid:2.16.840.1.113883.6.96
  • Publisher: SNOMED International; in the United States, the National Library of Medicine distributes it through the UMLS
  • Licence: Free in the United States through a UMLS licence, which each user holds for themselves.

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CPT

CPT (Current Procedural Terminology) codes the medical, surgical and diagnostic services and procedures clinicians report, most often on claims.
  • Status: Not served. CPT is licensed by the American Medical Association and requires a paid distributor licence per product. haau3 does not hold one, so this service will not answer about CPT codes at all.
  • URI: http://www.ama-assn.org/go/cpt
  • Also recognised as: CPT, urn:oid:2.16.840.1.113883.6.12
  • Publisher: American Medical Association (AMA)
  • Licence: Licensed by the AMA, product by product.

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ICD-10-CM

ICD-10-CM is the United States’ clinical modification of the World Health Organization’s ICD-10: the diagnosis codes US claims carry and medical records use for conditions and the reasons for a visit. A new release takes effect each October 1.
  • Status: Not served. ICD-10-CM is public domain and carries no licence restriction, but this service does not yet have a source configured for it.
  • URI: http://hl7.org/fhir/sid/icd-10-cm
  • Also recognised as: ICD10CM, ICD-10-CM, urn:oid:2.16.840.1.113883.6.90
  • Publisher: National Center for Health Statistics (NCHS), part of the CDC, under the World Health Organization’s authorization
  • Licence: Free to use, with no licence to sign.

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UCUM

UCUM (the Unified Code for Units of Measure) is the code system for units of measure that FHIR’s Quantity uses, such as mg, mL and mm[Hg].
  • Status: Not served. UCUM is a grammar rather than a list of codes, so it is validated by a unit parser rather than looked up on a terminology server. A lookup endpoint is the wrong shape for the question.
  • URI: http://unitsofmeasure.org
  • Also recognised as: UCUM, urn:oid:2.16.840.1.113883.6.8
  • Publisher: Regenstrief Institute
  • Licence: Free to use under Regenstrief’s UCUM terms.

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A system that is not listed

A request naming a system that is not served comes back as a FHIR OperationOutcome with an issue code of not-supported, saying which kind of no it is: a system nobody publishes, a system we are not licensed to serve, or one that needs a licence you hold rather than one we can pass on. The service does not guess. Systems that are not listed at all are also answered rather than errored. Most real-world coded data carries site-specific systems that no terminology server can resolve, so an honest “I do not recognise this” is a normal answer here, not a failure. This page is the service’s intent, generated from its registry so it cannot drift from the code. What a particular deployment is answering right now, including which release it holds of a code system it keeps itself, comes from GET /v1/fhir/r4/metadata?mode=terminology.