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THIS IS OUTDATED.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

This table changed in version 5.1 of the OMOP CDM. The field procedure_datetime was added.

The PROCEDURE_OCCURRENCE tabe contains records of activities or processes ordered by, or carried out by, a healthcare provider on the patient to have a diagnostic or therapeutic purpose. Procedures are present in various data sources in different forms with varying levels of standardization. For example:

  • Medical Claims include procedure codes that are submitted as part of a claim for health services rendered, including procedures performed.
  • Electronic Health Records that capture procedures as orders.
procedure_occurrence_idYesintegerA system-generated unique identifier for each Procedure Occurrence.
person_idYesintegerA foreign key identifier to the Person who is subjected to the Procedure. The demographic details of that Person are stored in the PERSON table.
procedure_concept_idYesintegerA foreign key that refers to a standard procedure Concept identifier in the Standardized Vocabularies.
procedure_dateYesdateThe date on which the Procedure was performed.
procedure_datetimeNodatetimeThe date and time on which the Procedure was performed.
procedure_type_concept_idYesintegerA foreign key to the predefined Concept identifier in the Standardized Vocabularies reflecting the type of source data from which the procedure record is derived.
modifier_concept_idNointegerA foreign key to a Standard Concept identifier for a modifier to the Procedure (e.g. bilateral)
quantityNointegerThe quantity of procedures ordered or administered.
provider_idNointegerA foreign key to the provider in the provider table who was responsible for carrying out the procedure.
visit_occurrence_idNointegerA foreign key to the visit in the visit table during which the Procedure was carried out.
procedure_source_valueNovarchar(50)The source code for the Procedure as it appears in the source data. This code is mapped to a standard procedure Concept in the Standardized Vocabularies and the original code is, stored here for reference. Procedure source codes are typically ICD-9-Proc, CPT-4, HCPCS or OPCS-4 codes.
procedure_source_concept_idNointegerA foreign key to a Procedure Concept that refers to the code used in the source.
qualifier_source_valueNovarchar(50)The source code for the qualifier as it appears in the source data.


  • Valid Procedure Concepts belong to the “Procedure” domain. Procedure Concepts are based on a variety of vocabularies: SNOMED-CT, ICD-9-Proc, CPT-4, HCPCS and OPCS-4, but also atypical Vocabularies such as ICD-9-CM or MedDRA.
  • Procedures are expected to be carried out within one day and therefore have no end date.
  • Procedures could involve the application of a drug, in which case the procedural component is recorded in the procedure table and simultaneously the administered drug in the drug exposure table when both the procedural component and drug are identifiable.
  • If the quantity value is omitted, a single procedure is assumed.
  • The Procedure Type defines from where the Procedure Occurrence is drawn or inferred. For administrative claims records the type indicates whether a Procedure was primary or secondary and their relative positioning within a claim.
  • The Visit during which the procedure was performed is recorded through a reference to the VISIT_OCCURRENCE table. This information is not always available.
  • The Provider carrying out the procedure is recorded through a reference to the PROVIDER table. This information is not always available.
documentation/cdm/procedure_occurrence.txt · Last modified: 2017/09/25 15:01 by clairblacketer