GET studies/{nctId}

clinicaltrials.gov:clinicaltrials.gov-api

Summary: Get a specific clinical study
Operation ID: getStudy
Auth: none

Retrieve complete, detailed information about a specific clinical trial using its NCT ID (National Clinical Trial identifier). Returns the full study record including all protocol information (title, description, design, eligibility criteria), status history, sponsor and investigator details, conditions being studied, interventions being tested, outcome measures, locations where the trial is conducted, and contact information. Use this endpoint when you already know the specific trial you want details for - typically after finding it via the search endpoint. The response is comprehensive (500KB+) and includes everything known about the trial including results data if available.

Original spec description

Returns detailed information about a specific clinical trial by its NCT ID (National Clinical Trial identifier, e.g., NCT01901835).

Usage Tips

- The NCT ID is case-insensitive but must be valid format (starts with NCT followed by 8 digits) - Response is very large (500KB+) - be prepared to handle big JSON payloads - Study may include resultsSection if results have been submitted - Use this after finding trials via /studies search, not for discovery - Consider caching results since study data changes infrequently - The hasResults flag indicates whether results data is available

Parameters (2)

fields (string, query, optional)

Comma-separated list of fields to return (reduces payload size)

nctId (string, path, required)

The NCT ID of the study (format: NCT followed by 8 digits)

Constraints: {'pattern': '^NCT[0-9]{8}$'}

Examples (7)

TitleTypeURLAction
Get trial by NCT ID openapi-spec https://clinicaltrials.gov/api/v2/studies/NCT00000102
Get study by NCT ID - COVID-19 vaccine trial curl https://clinicaltrials.gov/api/v2/studies/NCT04470427
Get study by NCT ID - Alzheimer's disease study curl https://clinicaltrials.gov/api/v2/studies/NCT02565511
Get study by NCT ID - Cancer immunotherapy trial curl https://clinicaltrials.gov/api/v2/studies/NCT03789097
Get study by NCT ID openapi-spec https://clinicaltrials.gov/api/v2/studies/NCT00281983
Get a specific clinical study openapi-spec https://clinicaltrials.gov/api/v2/studies/NCT01901835?fields=NCTId,BriefTitle,Condition
Get a specific clinical study probe-gate https://clinicaltrials.gov/api/v2/studies/NCT01901835?fields=NCTId%2CBriefTitle%2CCondition

Probe History

Latency

Status Codes

TimeStatusLatencySize
2026-03-23 10:51:01.191073 200 179ms
2026-03-23 10:48:31.448678 200 179ms
2026-03-23 10:21:51.454929 200 195ms
2026-03-23 09:31:50.792940 200 195ms
2026-03-23 09:06:05.216660 200 170ms
2026-03-23 09:03:02.432040 200 164ms 0.6MB
2026-03-22T21:45:47.148886 200 182ms

Response Changes

WhenOldNew
2026-03-23 09:03:02.432040 db57554cf25d 7cc3a0501512
2026-03-23 09:06:05.216660 7cc3a0501512 d893ab0f9d87
2026-03-23 09:31:50.792940 d893ab0f9d87 fe5ebccb7849
2026-03-23 10:21:51.454929 fe5ebccb7849 4f64b5c9037a
2026-03-23 10:48:31.448678 4f64b5c9037a 0fec5d7ca36b
2026-03-23 10:51:01.191073 0fec5d7ca36b db57554cf25d