The NLM value set authority center.

The Value Set Authority Center (VSAC) at the National Library of Medicine (NLM) provides downloadable access to all official versions of vocabulary value sets contained in the Clinical Quality Measures (CQMs) used in the certification criteria for electronic health record systems ("Meaningful Use" incentive program). Each value set consists of the numerical values (codes) and human-readable names (descriptions), drawn from standard vocabularies such as LOINC, RxNorm and SNOMED CT®, that are used to define clinical data elements used in clinical quality measures (e.g., patients with diabetes, tricyclic antidepressants). The content of the VSAC will gradually expand to incorporate value sets for other use cases, as well as for new measures and updates to existing measures.