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UMLS API Technical Documentation

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Check out the Postman sample collection to help you get started using the UMLS REST API.

API Terms of Service

Retrieving Semantic Type Information

The /semantic-network endpoint supports the retrieval of semantic type information by identifier.
UMLS CUIs are assigned semantic types. When you make a call to the /CUI/{CUI} service, you will receive back semantic type
information as part of your Concept object.

Use https://uts-ws.nlm.nih.gov/rest/semantic-network as your base URI.

Sample URI Description Returned JSON Object classType
/semantic-network/current/TUI/T109 Retrieves TUI SemanticType

Query Parameters

Parameter name Required? Y/N Description Valid Values Default value Usage Note
apiKey Y An API key is required for each call to the API. Visit your UTS profile to obtain your API key. n/a n/a n/a

Sample output for https://uts-ws.nlm.nih.gov/rest/semantic-network/2015AB/TUI/T109?apiKey=YOUR_APIKEY-…

Sample Output

{
   pageSize: 25,
   pageNumber: 1,
   pageCount: 1,
   result: {
        classType: "SemanticType",
        abbreviation: "orch",
        ui: "T109",
        definition: "The general class of carbon-containing compounds, usually based on carbon chains or rings, and also containing hydrogen (hydrocarbons), with or without nitrogen, oxygen, or other elements in which the bonding between elements is generally covalent.",
        example: "NONE",
        nonHuman: "NONE",
        usageNote: "Salts of organic chemicals (such as Calcium Acetate) would be considered organic chemicals and should not also receive the type 'Inorganic Chemical'.",
        treeNumber: "A1.4.1.2.1",
        semanticTypeGroup: {
            classType: "SemanticGroup",
            abbreviation: "CHEM",
            expandedForm: "Chemicals & Drugs",
            semanticTypeCount: 20
            },
        childCount: 2,
        name: "Organic Chemical"
    }
}