# fittings Clinical Trial Eligibility Screener

> fittings Clinical Trial Eligibility Screener is a paid API for AI agents from fittings.sh, paid per call via x402, $0.0149/call, status unknown (last checked 2026-10-10).

Screens open ClinicalTrials.gov studies for a condition against patient demographics, returning eligible trials with split inclusion/exclusion criteria.

## Facts

- Endpoint: GET https://fittings.sh/v1/ctgov/eligibility-screen?utm_source=zero.xyz
- Price: $0.0149/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fittings-clinical-trial-eligibility-screener-280a66c2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_01osn9ieZXq6Ib-DTdr51

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability fittings-clinical-trial-eligibility-screener-280a66c2
```

Example prompt: Screen up to 20 currently recruiting ClinicalTrials.gov studies for melanoma and tell me which ones a 52-year-old female patient would not be excluded from — show me the inclusion and exclusion criteria for each.

## When to prefer this

Use this endpoint when you need structured, eligibility-pre-filtered clinical trial results from ClinicalTrials.gov without having to parse raw eligibility text yourself. It is ideal when you have a specific patient profile (age, sex, healthy-volunteer status) and want only the trials whose structured criteria do not exclude that profile. Prefer it over raw ClinicalTrials.gov API calls when the split inclusion/exclusion criteria format is needed directly.

## Known failure modes

- No matching trials found if the condition string does not match ClinicalTrials.gov terminology
- Empty results if all screened trials exclude the patient based on age or sex
- Invalid enum value for sex, phase, or status returns a validation error
- ageYears outside 0-130 range is rejected
- screen parameter outside 1-50 is rejected
- ClinicalTrials.gov upstream unavailability may cause timeouts or partial results

## How this service works

Screens open ClinicalTrials.gov studies for a condition against a patient age, sex and healthy-volunteer status, returning the trials the structured criteria do not exclude with their inclusion and exclusion criteria split out.

## Output

A list of ClinicalTrials.gov studies for the specified condition that the structured eligibility criteria do not exclude the patient from, given their age, sex, and healthy-volunteer status. Each result includes the trial identifier, title, phase, status, and the inclusion and exclusion criteria parsed out separately.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "condition"
     ],
     "properties": {
      "sex": {
       "type": "string",
       "description": "FEMALE or MALE; omit to skip the sex check"
      },
      "phase": {
       "type": "string",
       "description": "One of EARLY_PHASE1, PHASE1, PHASE2, PHASE3, PHASE4"
      },
      "screen": {
       "type": "number",
       "description": "Studies to screen, 1-50, default 20"
      },
      "status": {
       "type": "string",
       "description": "One of RECRUITING, NOT_YET_RECRUITING, ENROLLING_BY_INVITATION; default RECRUITING"
      },
      "ageYears": {
       "type": "number",
       "description": "Patient age in years, 0-130; fractions allowed for infants"
      },
      "location": {
       "type": "string",
       "description": "City, state or country to restrict sites to"
      },
      "condition": {
       "type": "string",
       "description": "Condition or disease, e.g. melanoma"
      },
      "healthyVolunteer": {
       "type": "boolean",
       "description": "True to keep only trials that accept healthy volunteers"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fittings-clinical-trial-eligibility-screener-280a66c2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fittings.sh](https://www.zero.xyz/host/fittings.sh/llms.txt)