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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 UMLS Atoms

URIs | Query Parameters | Sample Output

URIs with /atoms support the following use cases:

Note that ‘current’ in the URI can always be used to search against the latest UMLS publication.
You may use any valid UMLS release back to 2008AA in your URI if you would like to search against a particular version of the UMLS.

URIs

The base URI is https://uts-ws.nlm.nih.gov/rest

Sample URI Description Returned JSON Object classType
/content/current/CUI/C0155502/atoms Retrieves all atoms for C0155502 - python example Atom
/content/current/CUI/C0155502/atoms/preferred Retrieves the default preferred atom of C0155502 Atom
/content/current/CUI/C0155502/atoms?language=ENG Retrieves all English language atoms for C0155502 Atom
/content/current/CUI/C0155502/atoms?sabs=SNOMEDCT_US,ICD9CM&ttys=PT Retrieve SNOMEDCT_US and ICD9CM preferred terms in C0155502 Atom
/content/current/source/SNOMEDCT_US/111541001/atoms Retrieve atoms belonging to SNOMED CT concept 111541001 - python example Atom
/content/current/source/SNOMEDCT_US/111541001/atoms/preferred Retrieve the default preferred atom belonging to SNOMED CT concept 111541001 Atom
/content/current/AUI/A8345234 Retrieve information about AUI A8345234 Atom
/content/current/AUI/A8345234/ancestors Retrieve ancestors of a UMLS atom Atom
/content/current/AUI/A8345234/descendants Retrieve descendants of a UMLS atom Atom
/content/current/AUI/A8345234/parents Retrieve parents of a UMLS atom Atom
/content/current/AUI/A8345234/children Retrieve children of a UMLS atom Atom

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
sabs N Comma-separated list of source vocabularies to include in your search Any root source abbreviation in the UMLS. See the “Abbreviation” column for a list of UMLS source vocabulary abbreviations. All UMLS source vocabularies Use a comma between each source abbreviation to specify more than one.
ttys N One or more term types Any valid term type in the UMLS All term types Use a comma between each term type to specify more than one.
language N Retrieve only atoms that have a specific language Any 3 letter language abbreviation in the UMLS, such as “ENG”,“FRE”,“SPA”,“GER”,“DUT”,“JPN”, etc All languages are returned by default Currently filtering by one language is supported.
includeObsolete N Include content that is obsolete according to the content provider or NLM. true or false false (except for atoms/preferred, which defaults to true) n/a
includeSuppressible N Include content that is suppressible according to NLM Editors. true or false false (except for atoms/preferred, which defaults to true) n/a
pageNumber N Whole number that specifies which page of results to fetch. 1,2,3, etc 1 n/a
pageSize N Whole number that specifies the number of results to include per page. 1,2,3, etc 25 n/a

Sample Output

Sample output for https://uts-ws.nlm.nih.gov/rest/content/current/CUI/C0155502/atoms?ttys=PT&sabs=SNOMEDCT_US%2CICD9CM&apiKey=YOUR_APIKEY…

{
	"pageSize" : 25,
	"pageNumber" : 1,
	"pageCount" : 1,
	"result" : [{
			"classType" : "Atom",
			"ui" : "A8345234",
			"suppressible" : "false",
			"obsolete" : "false",
			"rootSource" : "ICD9CM",
			"termType" : "PT",
			"code" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/source/ICD9CM/386.11",
			"concept" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/CUI/C0155502",
			"sourceConcept" : "NONE",
			"sourceDescriptor" : "NONE",
			"attributes" : "NONE",
			"parents" : "NONE",
			"ancestors" : null,
			"children" : "NONE",
			"descendants" : null,
			"relations" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/AUI/A8345234/relations",
			"name" : "Benign paroxysmal positional vertigo",
			"language" : "ENG"
		}, {
			"classType" : "Atom",
			"ui" : "A2892933",
			"suppressible" : "false",
			"obsolete" : "false",
			"rootSource" : "SNOMEDCT_US",
			"termType" : "PT",
			"code" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/source/SNOMEDCT_US/111541001",
			"concept" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/CUI/C0155502",
			"sourceConcept" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/source/SNOMEDCT_US/111541001",
			"sourceDescriptor" : "NONE",
			"attributes" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/AUI/A2892933/attributes",
			"parents" : "NONE",
			"ancestors" : null,
			"children" : "NONE",
			"descendants" : null,
			"relations" : "NONE",
			"name" : "Benign paroxysmal positional vertigo",
			"language" : "ENG"
		}, {
			"classType" : "Atom",
			"ui" : "A3101021",
			"suppressible" : "false",
			"obsolete" : "false",
			"rootSource" : "SNOMEDCT_US",
			"termType" : "PT",
			"code" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/source/SNOMEDCT_US/232285008",
			"concept" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/CUI/C0155502",
			"sourceConcept" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/source/SNOMEDCT_US/232285008",
			"sourceDescriptor" : "NONE",
			"attributes" : "https://uts-ws.nlm.nih.gov/rest/content/2016AA/AUI/A3101021/attributes",
			"parents" : "NONE",
			"ancestors" : null,
			"children" : "NONE",
			"descendants" : null,
			"relations" : "NONE",
			"name" : "Benign recurrent vertigo",
			"language" : "ENG"
		}
	]
}