Observations are a generic set to capture all clinical findings, observations, complaints, and medical history, as they are reported in the data, as well as laboratory and radiological tests and their results. There are three Standard Vocabularies defined for observations:
- Laboratory tests and values: Logical Observation Identifiers Names and Codes (LOINC) is a coding systems maintained by the Regenstrief Institute – vocabulary_id 6.
- Regenstrief also maintains the "LOINC Multidimensional Classification" – vocabulary_id 49.
- Qualitative lab results: A set of SNOMED-CT Qualifier Value concepts – vocabulary_id 1.
- Laboratory units: Unified Code for Units of Measure (UCUM), maintained by the UCUM Organization – vocabulary_id 11.
- All other findings and observables: SNOMED-CT - vocabulary_id 1.
The Systematized Nomenclature of Medicine, Clinical Terms (SNOMED-CT), is maintained by the International Health Terminology Standards Development Organization (IHTSDO).