The following Standard Vocabularies are defined for the Cost domain.
- Diagnosis-Related Groups (DRG) as implemented by the Centers for Medicare and Medicaid Services for the Medicare Part A "Inpatient Prospective Payment System (IPPS) For Acute Care Inpatient Hospital Stays" – vocabulary_id 40.
- Major Diagnostic Categories (MDC) as implemented by the Centers for Medicare and Medicaid Services as a classification system for DRGs – vocabulary_id 41.
- Ambulatory Payment Classification (APC) as implemented by the Centers for Medicare and Medicaid Services for the Medicare Part A " Prospective Payment System for Hospital Outpatient Department Services" – vocabulary_id 42.
- Revenue code system defined by the National Uniform Billing Committee (NUBC) for the UB-04 claim form (Revenue Codes) – vocabulary_id 43.
In the Standard Vocabulary, both DRG and MS-DRG are implemented under vocabulary_id 40 with full validity information (valid_start_date, valid_end_date). In 2007 after version 25, DRG was revised to MS-DRG with a completely new numbering system, which means that the concept_codes in DRG are not unique (however, the concept_ids are). The change from concept_class "DRG" and "MS-DRG" distinguishes this major revision. Relationship_id 299 links DRG to the corresponding MS-DRG.
APC and Revenue Codes are implemented as a flat concept_level 1 set of concepts with no classifications or cross-references.
Cost domain concepts are listed in the Source_To_Concept_Map as records linking the codes to the corresponding concept_ids. No other mapping information is available.