ClinicalTrials Study Count¶
Queries ClinicalTrials.gov (API v2) for the number of studies that match a given condition or disease. Returns a concise summary when JSON is selected, including total_studies and basic query metadata, or the raw text when CSV is selected.
Usage¶
Use this node to quickly gauge how many clinical studies exist for a particular condition before running more detailed searches or fetching study details. It fits early in a workflow to assess query scope, refine search terms, or decide whether to paginate or filter further.
Inputs¶
| Field | Required | Type | Description | Example |
|---|---|---|---|---|
| condition_or_disease | True | STRING | The search query string for a condition, disease, or term to match studies. | lung cancer |
| format | True | ['json', 'csv'] | The desired output format. JSON returns a structured summary with total_studies; CSV returns raw text from the API. | json |
| fields | False | STRING | Comma-separated list of additional fields to include in the API response. Optional and typically unnecessary when only the count is needed. | NCTId,BriefTitle,OverallStatus |
Outputs¶
| Field | Type | Description | Example |
|---|---|---|---|
| results | STRING | When format=json, a pretty-printed JSON string containing total_studies, query info, and raw API data. When format=csv, the raw CSV text from the API. | { "data": { ... }, "query": "lung cancer", "total_studies": 12456, "min_rank": 1, "max_rank": 1, "api_version": "2.0" } |
| metadata | STRING | A JSON string with metadata about the request. For JSON output: includes query, format, and api_version. For CSV output: includes query, format, and content_length. | { "query": "lung cancer", "format": "json", "api_version": "2.0" } |
Important Notes¶
- JSON vs CSV behavior: JSON returns a structured summary including total_studies. CSV returns the raw response text; the count is not extracted for you.
- Supported formats: Inputs accept json or csv. The node internally handles non-JSON formats by returning raw text.
- Search parameter: The primary query parameter used is query.cond set to the value of condition_or_disease.
- Optional fields: Specifying fields can alter the API payload; it is not required to obtain the total study count.
- Error handling: On network or JSON parsing issues, the node returns a simple error JSON string in both outputs.
Troubleshooting¶
- No or low counts returned: Refine condition_or_disease (use broader terms or synonyms) and try again.
- Unexpected raw text in results: Ensure format is set to json if you expect a parsed JSON summary with total_studies.
- Timeouts or network errors: Check internet connectivity and try again later; the service may be temporarily unavailable.
- Invalid or empty fields: Remove or correct the fields parameter if the API returns unexpected content, then retry with only the condition and format.
- CSV content length is zero: The API may have returned no rows for the query; verify the search term or switch to JSON for clearer diagnostics.