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THIS IS OUTDATED. All documentation is now on the github wiki. Please refer there or to the CDM working group for more information

The CONCEPT_CLASS table is a reference table, which includes a list of the classifications used to differentiate Concepts within a given Vocabulary. This reference table is populated with a single record for each Concept Class:

concept_class_idYesvarchar(20)A unique key for each class.
concept_class_nameYesvarchar(255)The name describing the Concept Class, e.g. “Clinical Finding”, “Ingredient”, etc.
concept_class_concept_idYesintegerA foreign key that refers to an identifier in the CONCEPT table for the unique Concept Class the record belongs to.


  • There is one record for each Concept Class. Concept Classes are used to create additional structure to the Concepts within each Vocabulary. Some Concept Classes are unique to a Vocabulary (for example “Clinical Finding” in SNOMED), but others can be used across different Vocabularies. The separation of Concepts through Concept Classes can be semantically horizontal (each Class subsumes Concepts of the same hierarchical level, akin to sub-Vocabularies within a Vocabulary) or vertical (each Class subsumes Concepts of a certain kind, going across hierarchical levels). For example, Concept Classes in SNOMED are vertical: The classes “Procedure” and “Clinical Finding” define very granular to very generic Concepts. On the other hand, “Clinical Drug” and “Ingredient” Concept Classes define horizontal layers or strata in the RxNorm vocabulary, which all belong to the same concept of a Drug.
  • The concept_class_id field contains an alphanumerical identifier, that can also be used as the abbreviation of the Concept Class.
  • The concept_class_name field contains the unabbreviated names of the Concept Class.
  • Each Concept Class also has an entry in the Concept table, which is recorded in the concept_class_concept_id field. This is for purposes of creating a closed Information Model, where all entities in the OMOP CDM are covered by unique Concepts.
  • Past versions of the OMOP CDM did not have a separate reference table for all Concept Classes. Also, the content of the old concept_class and the new concept_class_id fields are not always identical. A conversion talbe can be found here:
concept_class previouslyconcept_class_id Version 5
Administrative conceptAdmin Concept
Admitting SourceAdmitting Source
Anatomical Therapeutic Chemical ClassificationATC
Anatomical Therapeutic Chemical ClassificationATC
Biobank FlagBiobank Flag
Biological functionBiological Function
Body structureBody Structure
Brand NameBrand Name
Branded DrugBranded Drug
Branded Drug ComponentBranded Drug Comp
Branded Drug FormBranded Drug Form
Branded PackBranded Pack
Chart AvailabilityChart Availability
Chemical StructureChemical Structure
Clinical DrugClinical Drug
Clinical Drug ComponentClinical Drug Comp
Clinical Drug FormClinical Drug Form
Clinical findingClinical Finding
Clinical PackClinical Pack
Concept RelationshipConcept Relationship
Condition Occurrence TypeCondition Occur Type
Context-dependent categoryContext-dependent
Death TypeDeath Type
Device TypeDevice Type
Discharge DispositionDischarge Dispo
Discharge StatusDischarge Status
Dose FormDose Form
DRGDiagnostic Category
Drug Exposure TypeDrug Exposure Type
Drug InteractionDrug Interaction
Encounter TypeEncounter Type
Enhanced Therapeutic ClassificationETC
Enrollment BasisEnrollment Basis
Environment or geographical locationLocation
Health Care Provider SpecialtyProvider Specialty
HES specialtyProvider Specialty
High Level Group TermHLGT
High Level TermHLT
Indication or Contra-indicationInd / CI
LOINC CodeMeasurement
LOINC Multidimensional ClassificationMeas Class
Lowest Level TermLLT
MDCDiagnostic Category
Measurement TypeMeas Type
Mechanism of ActionMechanism of Action
Model componentModel Comp
Morphologic abnormalityMorph Abnormality
MS-DRGDiagnostic Category
Namespace conceptNamespace Concept
Note TypeNote Type
Observable entityObservable Entity
Observation Period TypeObs Period Type
Observation TypeObservation Type
OMOP DOI cohortDrug Cohort
OMOP HOI cohortCondition Cohort
Patient StatusPatient Status
Pharmaceutical / biologic productPharma/Biol Product
Pharmaceutical PreparationsPharma Preparation
Pharmacologic ClassPharmacologic Class
Physical forcePhysical Force
Physical objectPhysical Object
Physiologic EffectPhysiologic Effect
Place of ServicePlace of Service
Preferred TermPT
Procedure Occurrence TypeProcedure Occur Type
Qualifier valueQualifier Value
Record artifactRecord Artifact
Revenue CodeRevenue Code
Social contextSocial Context
Special conceptSpecial Concept
Staging and scalesStaging / Scales
Standardized MedDRA QuerySMQ
System Organ ClassSOC
Therapeutic ClassTherapeutic Class
UCUM CanonicalCanonical Unit
UCUM CustomUnit
UCUM StandardUnit
VA ClassDrug Class
VA Drug InteractionDrug Interaction
VA ProductDrug Product
Visit TypeVisit Type
documentation/cdm/concept_class.txt · Last modified: 2017/09/25 14:58 by clairblacketer