Skip to content

Standardized Medical Coding Systems

These standard vocabularies are essential for defining phenotypes and conducting research with electronic health records (EHR).

CPT (Current Procedural Terminology)

Maintained by the American Medical Association (AMA), CPT codes are used to describe medical, surgical, and diagnostic services.

  • Official Source: AMA CPT Overview
  • CPT Dictionary by CDC: CPT Dictionary
  • Correlated Table: procesdure_occurrence
  • OHDSI Context: Mapped to the Procedure domain in the OMOP Common Data Model.

RxNorm

Produced by the National Library of Medicine (NLM), RxNorm provides normalized names for clinical drugs and links its names to many of the drug vocabularies used in pharmacy management and drug interaction software.

  • Official Source: NLM RxNorm
  • Browser: RxNav
  • Correlated Table: drug_exposure
  • OHDSI Context: The standard vocabulary for the Drug domain in OMOP.

LOINC (Logical Observation Identifiers Names and Codes)

Maintained by the Regenstrief Institute, LOINC is the international standard for identifying health measurements, observations, and documents (e.g., lab tests).

  • Official Source: LOINC.org
  • Search: Search LOINC
  • Correlated Table: measurement, observation
  • OHDSI Context: The standard vocabulary for the Measurement and Observation domains in OMOP.

ICD (International Classification of Diseases)

Maintained by the World Health Organization (WHO) and adapted by various countries (e.g., ICD-10-CM by CMS in the US). It is used for diagnosis coding.

  • Official Source (WHO): ICD-11
  • US Adaptation (CMS ICD-10-CM): CMS ICD-10
  • Correlated Table: condition_occurrence
  • OHDSI Context: Standard diagnosis codes, often mapped to SNOMED CT for analysis in OMOP.