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National Institutes of Health (NIH)

National Institutes of Health (NIH) Studies API

Related to clinical trial studies

Documentation Provider Profile APIs.io OpenAPI GitHub

National Institutes of Health (NIH) Studies API is one of 15 APIs that National Institutes of Health (NIH) publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

Tagged areas include Studies. The published artifact set on APIs.io includes an OpenAPI specification and API documentation.

This API exposes 5 operations across 5 paths, and defines 144 schemas. It is described by OpenAPI 3.2.0, at version 2.0.5.

Requests are made against a single base URL, https://clinicaltrials.gov/api/v2.

5 operations 5 paths 144 schemas 5 GET

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.2.0
API Version
2.0.5
Base URL
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
Resource Areas
1

Paths & Operations 5

Across 5 paths, the API surfaces 5 operations — 5 GET. Each is listed below with its method, path, parameters, and response codes.

Studies 5

Related to clinical trial studies

GET
/studies
Studies
listStudies 29 params → 200400
GET
/studies/{nctId}
Single Study
fetchStudy 4 params → 200301400404
GET
/studies/metadata
Data Model Fields
studiesMetadata 2 params → 200400
GET
/studies/search-areas
Search Areas
searchAreas → 200400
GET
/studies/enums
Enums
enums → 200400

Schemas 144

The contract defines 144 schemas that model the data the API accepts and returns. The most detailed are StatusModule (21 properties), MeasureAnalysis (21 properties), OutcomeMeasure (17 properties), FieldNode (16 properties). Each schema is shown below with its type and property counts.

AgreementRestrictionType
string
DescriptionModule
object
2 properties
NonInferiorityType
string
FirstMcpInfo
object
1 property
EnrollmentType
string
RecruitmentStatus
string
MeasureParam
string
DateTimeMinutes
string
Date and time in yyyy-MM-dd'T'HH:mm format
ProtocolSection
object
13 properties
EligibilityModule
object
10 properties
SearchDocumentList
array
AvailIpd
object
4 properties
Contact
object
5 properties
ObservationalModel
string
SecondaryIdType
string
ConfidenceIntervalNumSides
string
AdverseEventsModule
object
7 properties
BrowseModule
object
4 properties
StudyList
array
study field values of type markup are in markdown format.
MoreInfoModule
object
3 properties
DropWithdraw
object
3 properties
UnpostedAnnotation
object
2 properties
DateStruct
object
2 properties
ExpandedAccessInfo
object
3 properties
SeeAlsoLink
object
2 properties
GeoPoint
object
2 properties 2 required
StandardAge
string
BrowseLeafRelevance
string
UnpostedEvent
object
3 properties
EventGroup
object
9 properties
FieldNodeList
array
PartialDate
string
Date in yyyy, yyyy-MM, or yyyy-MM-dd format
OfficialRole
string
OutcomeMeasure
object
17 properties
StudyType
string
DesignMasking
string
DenomCount
object
2 properties
Intervention
object
5 properties
ViolationEventType
string
CertainAgreement
object
4 properties
Measurement
object
6 properties
AgencyClass
string
DocumentSection
object
1 property
ResultsSection
object
5 properties
Outcome
object
3 properties
ExpandedAccessTypes
object
3 properties
MeasureClass
object
3 properties
DateType
string
InterventionalAssignment
string
Denom
object
2 properties
FieldNode
object
16 properties 4 required
Location
object
8 properties
StudiesCsv
string
Study objects in csv file
ContactRole
string
OrgStudyIdInfo
object
3 properties
AnnotationModule
object
2 properties
StudiesZip
string
Study objects as files in zip archive
OutcomeMeasuresModule
object
1 property
ResponsibleParty
object
6 properties
ResponsiblePartyType
string
SubmissionInfo
object
5 properties
WebLink
object
2 properties 2 required
ReferencesModule
object
3 properties
FlowStats
object
4 properties
PrimaryPurpose
string
BaselineCharacteristicsModule
object
5 properties
BrowseLeaf
object
4 properties
StatusModule
object
21 properties
ConditionsModule
object
2 properties
Retraction
object
2 properties
PartialDateStruct
object
2 properties
Reference
object
4 properties
EventAssessment
string
MeasureCategory
object
2 properties
EnumInfo
object
3 properties 3 required
Study
object
6 properties
StudyFhir
object
Study in FHIR JSON format
nct
string
NCT number
EnumInfoList
array
SamplingMethod
string
ViolationAnnotation
object
1 property
OutcomeMeasureType
string
DesignInfo
object
7 properties
ParticipantFlowModule
object
5 properties
IpdSharing
string
BioSpec
object
2 properties
IpdSharingInfoType
string
EnumItem
object
3 properties 2 required
EventStats
object
4 properties
AnalysisDispersionType
string
InterventionType
string
ExpandedAccessStatus
string
ReferenceType
string
GeoName
string
State/province or city name
SubmissionTracking
object
3 properties
MeasureAnalysis
object
21 properties
BrowseBranch
object
2 properties
Organization
object
2 properties
Status
string
BaselineMeasure
object
10 properties
DerivedSection
object
3 properties
AnnotationSection
object
1 property
ViolationEvent
object
6 properties
BioSpecRetention
string
DesignAllocation
string
ContactsLocationsModule
object
3 properties
ArmGroupType
string
PointOfContact
object
5 properties
ReportingStatus
string
LargeDoc
object
9 properties
SearchPart
object
5 properties 5 required
DesignTimePerspective
string
PagedStudies
object
3 properties 1 required
Phase
string
WhoMasked
string
MeasureDispersionType
string
EnrollmentInfo
object
2 properties
ArmsInterventionsModule
object
2 properties
AdverseEvent
object
6 properties
FlowMilestone
object
3 properties
SearchDocument
object
2 properties 2 required
SponsorCollaboratorsModule
object
3 properties
MaskingBlock
object
3 properties
errorMessage
string
A text message describing an error
LargeDocumentModule
object
2 properties
DesignModule
object
9 properties
OversightModule
object
7 properties
UnpostedEventType
string
OutcomesModule
object
3 properties
FlowGroup
object
3 properties
OrgStudyIdType
string
IdentificationModule
object
8 properties
Sex
string
LimitationsAndCaveats
object
1 property
MiscInfoModule
object
3 properties
ArmGroup
object
4 properties
Sponsor
object
2 properties
FlowPeriod
object
3 properties
SearchArea
object
4 properties 2 required
Official
object
3 properties
Mesh
object
2 properties
MeasureGroup
object
3 properties
IpdSharingStatementModule
object
6 properties
SecondaryIdInfo
object
4 properties

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

nih-studies-api-openapi.yml Raw ↑

Other APIs National Institutes of Health (NIH) publishes across the network.

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NCBI BLAST URL API
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PubMed Central (PMC) OA API
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National Institutes of Health (NIH) BioSample API
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National Institutes of Health (NIH) Gene API
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National Institutes of Health (NIH) Genome API
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National Institutes of Health (NIH) Organelle API
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National Institutes of Health (NIH) Stats API
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National Institutes of Health (NIH) Taxonomy API
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#Studies
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API Details
ID
nih:nih-studies-api
Base URL
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
Docs
https://www.ncbi.nlm.nih.gov/home/develop/api/
Provider
National Institutes of Health (NIH)
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