United States Patient Care Summary (US-PCS) Implementation Guide - Downloaded Version 1.0.0 See the Directory of published versions

Terminology Guidance

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The International Patient Summary (IPS) has preferred bindings to several terminologies that vary from US Core terminology expectations. While this guide does not provide full mapping guidance, which would require considerations at the ValueSet level for each respective clinical profile, the table below summarizes coding system difference for implementer awareness and use when possible.

US Core to IPS Terminology Considerations

US-PCS Mandatory and Must Support Sections

Data Section (FHIR Resource)	US Core Terminology	IPS Terminology	Guidance
Allergies (AllergyIntolerance)	RxNorm, SNOMED CT US Edition	SNOMED CT, WHO ATC	Sending SNOMED CT or WHO ATC concepts preferred
Problem List (Condition)	SNOMED CT US Edition, ICD-10-CM	SNOMED CT	Sending SNOMED CT concepts preferred
Medication Summary (MedicationRequest)	RxNorm	SNOMED CT, WHO ATC	Sending SNOMED CT or WHO ATC concepts preferred
Encounters (Encounter)	SNOMED CT US Edition, CPT	No terminology guidance	Sending SNOMED CT concepts preferred
Immunizations (Immunization)	CVX	SNOMED CT, WHO ATC	Sending SNOMED CT concepts preferred
Procedures (Procedure)	SNOMED CT US Edition, LOINC, CPT, CDT, ICD-10-PCS, HCPCS	SNOMED CT	Sending SNOMED CT concepts preferred
Results (Observation & DiagnosticReport)	LOINC	LOINC	Terminologies aligned

US-PCS Optional Sections from IPS

Data Section (FHIR Resource)	US Core Terminology	IPS Terminology	Guidance
Advance Directives (Consent)	No terminology guidance	No terminology guidance	N/A
Alerts (Flag)	No terminology guidance	No terminology guidance	N/A
Functional Status (Condition)	SNOMED CT US Edition, ICD-10-CM	SNOMED CT	Sending SNOMED CT concepts preferred
Medical Devices (Device & DeviceUseStatement)	SNOMED CT US Edition	SNOMED CT	Sending SNOMED CT concepts preferred
History of Past Problems (Condition)	SNOMED CT US Edition, ICD-10-CM	SNOMED CT	Sending SNOMED CT concepts preferred
History of Pregnancy (Observation)	LOINC (code), SNOMED CT US Edition (value)	LOINC (code), SNOMED CT (value)	LOINC aligned although differences in SNOMED CT valuesets
Patient Story (Any resource permitted)	No terminology guidance	No terminology guidance	N/A
Plan of Care (CarePlan)	No terminology guidance	No terminology guidance	N/A
Social History	LOINC (code), SNOMED CT US Edition (value)	LOINC (code), SNOMED CT (value)	LOINC aligned although differences in SNOMED CT valuesets
Vital Signs	LOINC	LOINC	Terminologies aligned

Using SNOMED in IPS

The Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT) is licensed and available for use in the United States and has a national terminology subgroup in the US Edition of SNOMED CT. In addition, SNOMED CT is the preferred vocabulary for most clinical domains in the context of IPS. Therefore, it is encouraged to leverage codes from SNOMED CT when possible. While United States implementations may use concepts from the US Edition to support national requirements, implementers should preferentially select concepts that originate in the International Edition when clinically appropriate and sufficiently expressive for cross-border usage. Doing so promotes semantic interoperability across jurisdictions, reduces the need for cross-edition mappings, and improves the consistency of information exchange between US-based systems and international IPS implementations.

Adding Translation Concept Codes from US Terminologies to SNOMED CT

Terminology mappings between US Core and IPS can be informed by resources from the U.S. National Library of Medicine (NLM) with the Unified Medical Language System (UMLS) Metathesaurus serving as the primary source for identifying semantic equivalence across terminology systems. The UMLS integrates concepts and relationships from SNOMED CT, LOINC, RxNorm, ICD-10-CM, and numerous other clinical vocabularies, making it a valuable resource for implementing mapping between US Core and IPS terminology bindings. Note that while binding may be required or extensible in US Core, terminology bindings in IPS are only preferred. Therefore, while including international friendly concepts is encouraged, it is not required for IPS conformance.

FHIR representation of translation concepts: When an element uses CodeableConcept, the original US terminology code and an international translation may be included as separate Coding entries within the same CodeableConcept. The US coding used to satisfy the applicable US Core binding can be retained, with the mapped SNOMED CT or other IPS-preferred coding added as a translation. Translation codings represent the same concept, follow established mappings when available, and do not alter the applicable binding requirements.

• While mapping to IPS-preferred terms remains optional for US-PCS implementers, document creators SHOULD reference published mapping resources and SHOULD NOT create custom maps to IPS concepts whenever possible.^{§terminology-1}

• Document creators SHOULD retain US codes and concepts when adding international concepts.^{§terminology-2}