Skip to main content

Commonly Used Terminologies

This guide provides a comprehensive reference for the most commonly used code systems and valuesets in healthcare applications. Each section includes the FHIR system URLs needed for proper coding in FHIR resources.

Overview of Common Code Systems

The following table shows the most commonly used code system for each clinical application area:

Clinical ApplicationPrimary Code SystemCodeSystem URLDescriptionFull System Valueset
Clinical FindingsLOINChttp://loinc.orgLaboratory tests, vital signs, clinical observationshttp://loinc.org/vs
MedicationsRXNormhttp://www.nlm.nih.gov/research/umls/rxnormNormalized medication nameshttp://www.nlm.nih.gov/research/umls/rxnorm/vs
ProceduresCPThttp://www.ama-assn.org/go/cptCurrent Procedural Terminologyhttp://www.ama-assn.org/go/cpt/vs
DiagnosesICD-10-CMhttp://hl7.org/fhir/sid/icd-10-cmInternational Classification of Diseases, Clinical Modificationhttp://hl7.org/fhir/sid/icd-10-cm/vs
VaccinesCVXhttp://hl7.org/fhir/sid/cvxVaccine Administeredhttp://hl7.org/fhir/sid/cvx/vs
Allergies (food + environmental)SNOMED CThttp://snomed.info/sctSubstance and clinical conceptshttp://snomed.info/sct/vs

Use-case Specific ValueSets

Each clinical area has predefined sets of codes that cover the most common scenarios you'll encounter. While each clinical area has a primary code system, healthcare applications often need to support multiple coding systems for different use cases.

Clinical Findings and Laboratory Tests

Valueset NameDescriptionValueset URLExample ValuesCode Systems
Vital Signs TypeCodes for types of vital sign measurements and clinical observationshttp://hl7.org/fhir/us/core/ValueSet/us-core-vital-signs[8302-2] Body height, [8867-4] Heart rate,LOINC
Smoking StatusCodes for patient smoking status and tobacco usehttp://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113883.11.20.9.38[8517006] Ex-smokerSNOMED CT
Pregnancy StatusCodes for pregnancy status and related observationshttp://hl7.org/fhir/us/core/ValueSet/us-core-pregnancy-status[77386006] PregnancySNOMED CT
SDOH AssessmentSocial determinants of health assessment codeshttp://hl7.org/fhir/us/core/ValueSet/us-core-common-sdoh-assessments[71802-3] Housing statusLOINC
Sexual OrientationCodes for sexual orientation and gender identityhttp://hl7.org/fhir/us/core/ValueSet/us-core-sexual-orientation[20430005] HeterosexualSNOMED CT

Allergies and Adverse Reactions

Allergy coding uses SNOMED CT for substance identification and RXNorm for medication allergies, following US Core 5.0.1 specifications.

Code SystemSystem URLDescriptionUse Cases
SNOMED CThttp://snomed.info/sctSubstance and clinical conceptsFood allergies, environmental allergies, clinical findings
RXNormhttp://www.nlm.nih.gov/research/umls/rxnormMedication substancesDrug allergies, medication intolerances

Common ValueSets

Valueset NameDescriptionValueset URLExample ValuesCode Systems
US Core Allergy SubstanceCommon substances for allergy and intolerance documentation including refutationshttp://cts.nlm.nih.gov/fhir/ValueSet/2.16.840.1.113762.1.4.1186.8[7980] Penicillin GSNOMED CT, RXNorm

Medications

For detailed information about medication coding systems including RxNorm and NDC, see Medication Code Systems.

Medical Procedures

Procedure coding varies by setting and purpose, with CPT being primary for billing.

Code SystemSystem URLDescriptionUse Cases
CPThttp://www.ama-assn.org/go/cptCurrent Procedural TerminologyBilling, procedure documentation
HCPCShttps://www.cms.gov/Medicare/Coding/HCPCSReleaseCodeSetsHealthcare Common Procedure Coding SystemMedicare/Medicaid billing, Value-based care, DME
SNOMED CThttp://snomed.info/sctClinical procedure conceptsClinical documentation, procedure notes
ICD-10-PCShttp://www.cms.gov/Medicare/Coding/ICD10ICD-10 Procedure Coding SystemHospital inpatient billing

Diagnoses and Conditions

Diagnosis coding primarily uses ICD-10-CM for standardized disease classification, with SNOMED CT providing more granular clinical concepts preferred in international settings.

Code SystemSystem URLDescriptionUse Cases
ICD-10-CMhttp://hl7.org/fhir/sid/icd-10-cmInternational Classification of Diseases, Clinical ModificationPrimary diagnoses, billing, epidemiology
SNOMED CThttp://snomed.info/sctClinical findings and disordersClinical documentation, problem lists

Vaccines and Immunizations

Vaccine coding uses CVX codes for vaccine types and CPT codes for administration procedures.

Code SystemSystem URLDescriptionUse Cases
CVXhttp://hl7.org/fhir/sid/cvxVaccine AdministeredImmunization records, vaccine administration
CPThttp://www.ama-assn.org/go/cptVaccine administration proceduresBilling for vaccine administration