Procedure Domain

Three common procedure code systems are supported in the Standard Vocabulary:
  • The International Statistical Classification of Diseases and Related Health Problems, Clinical Modification, Volume 3 (ICD-9-Procedure) codes maintained by the National Center for Health Statistics (NCHS) – vocabulary_id 3.
  • The American Medical Association produce the Current Procedural Terminology (CPT-4) – vocabulary_id 4.
  • The Healthcare Common Procedure Coding System (HCPCS) Level II codes maintained by the Center for Medicare and Medicaid Services (CMS) – vocabulary_id 5.

All three are used for the OMOP Standard Vocabulary as low-level concept codes for procedures. These low-level codes are linked to SNOMED-CT “Procedure” concepts (figure 6) for classification purposes.

As described above, all of SNOMED-CT is loaded into the Concept table, providing the Standard Vocabulary for Conditions and Procedures. The other concepts are available for the convenience of the researcher, but only concepts of the concept_class “Procedure” (similar to "Clinical Finding") are designated Standard Vocabulary concepts with a concept_level greater than 0.

ICD-9-Procedure, CPT-4 and HCPCS concepts are loaded from their respective sources, together with their relationships to SNOMED-CT.