Cross-Mappings
Unified Medical Language System(UMLS)
NLM's terminology integration layer with over 220 source vocabularies unified by Concept Unique Identifiers (CUIs).
Definition
The Unified Medical Language System (UMLS) is the U.S. National Library of Medicine's terminology integration layer. The Metathesaurus integrates more than 220 source vocabularies (ICD-10-CM, ICD-10, SNOMED CT, LOINC, RxNorm, MeSH, ICD-9-CM, CPT, HCPCS, ICD-O, OMIM, NCBI Taxonomy, and many more) by clustering equivalent concepts into Concept Unique Identifiers (CUIs).
Each CUI starts with the letter C followed by a 7-digit number (e.g., C0011860 for diabetes mellitus, type 2). All synonyms across all source vocabularies for the same concept share that CUI, making UMLS the canonical bridge between source systems.
UMLS also publishes the Semantic Network (a higher-level type system: "Disease or Syndrome", "Pharmacologic Substance", etc.) and the SPECIALIST Lexicon. It is the foundation that AutoICD uses to build cross-mappings between ICD-10-CM, SNOMED CT, ICD-11, and other code systems.
When to use
- •Building a single-search clinical reference across heterogeneous code systems.
- •Migrating data from one terminology to another (e.g., ICD-9-CM → ICD-10-CM via shared CUIs).
- •NLP pipelines that need a common semantic ID before downstream processing.
Try it in AutoICD API
Translate an ICD-10 code into UMLS CUIs
curl -X POST https://autoicdapi.com/v1/translate \
-H "Authorization: Bearer $AUTOICD_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"code": "E11.9",
"from": "icd10",
"to": "umls"
}'Language: bash. View full API docs · Get an API key.