Terminology Validation
Code validation against 129 integrated vocabularies
Terminology validation goes beyond table bindings to check coded values against external vocabulary standards. This layer requires an API connection (not available in Offline Mode).
Supported Vocabularies
LOINC
Laboratory and clinical observation codes (100,000+ concepts)
SNOMED CT
Clinical terminology for diagnoses, procedures, and findings
ICD-10-CM / PCS
Diagnosis and procedure classification codes
RxNorm
Medication names, ingredients, and dose forms
HL7 Tables (THO)
HL7 Terminology (terminology.hl7.org) code systems and value sets
OMOP Vocabularies
Additional vocabularies via the OMOP Common Data Model
Units of Measure
UCUM is a productive grammar, not a fixed list of codes — prefixes and atoms compose without limit, so no enumerated code set can decide whether a unit is valid. Units in OBX-6 are parsed against the UCUM grammar itself, using the National Library of Medicine’s UCUM implementation. Legitimate compositions such as mL/min/{1.73_m2} validate correctly even though no vocabulary list contains them.
Unit validity
Checked against the UCUM grammar rather than a harvested code list, so valid units are not rejected and invented ones are not accepted
Unit vs. what the code measures
A unit is compared against the LOINC PROPERTY of the code in OBX-3. A result coded as a mass concentration but reported in mmol/L is flagged — the classic US/SI mix-up that unit-level checking cannot see, because mmol/L is a perfectly valid unit, just not for that code
What a Match Tells You
A successful match expands to the concept’s full detail, not just a tick. For LOINC that includes the six axes that define what the code means — component, property, timing, system, scale and method. LOINC 6690-2 resolves to Leukocytes / number concentration / point in time / blood / quantitative / automated count, which is what makes a disagreement elsewhere in the message visible.
LOINC axes
Component, property, timing, system, scale and method, shown in reading order
Standard concept flag
Whether the code is the standard representation, a classification, or valid but non-standard
Synonyms, hierarchy and mappings
Parents and children, and cross-vocabulary mappings, without leaving the panel
Codes Missing From a Version’s Table
HL7 tables gained values over time, so a code that is perfectly valid today may be absent from the table as published in an older version. Rather than reporting an error, the code is checked against HL7 Terminology (THO) and reported as valid, with the provenance available behind a disclosure so a long result message is not filled with the same sentence repeated per segment.
Display names are matched against the concept name and its synonyms, not by exact string equality — so a locally-worded display that means the same thing is not reported as a mismatch.
When a Code Cannot Be Judged
Some code systems are licence-restricted or not loaded. Those are reported as unvalidatable — an explicit “we cannot judge this” — never as invalid. A validator that reports absence as failure teaches people to ignore it.
Terminology validation requires an active API connection. In Offline Mode, only schema-level table checks are performed.