# LOINC Laboratory Code Lookup

> LOINC Laboratory Code Lookup is a paid API for AI agents from api.healthtravel-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-29).

Searches Regenstrief LOINC codes by term and returns matching LOINC numbers and long common names via NLM Clinical Tables

## Facts

- Endpoint: GET https://api.healthtravel-api.workers.dev/api/health/loinc-laboratory-codes?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/loinc-laboratory-code-lookup-e6b3e556
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZJ7g7Q5UgtSLrUmyBSIw5

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 loinc-laboratory-code-lookup-e6b3e556
```

Example prompt: Can you look up LOINC codes matching 'hemoglobin A1c' and give me the top 5 results with their LOINC numbers and long names?

## When to prefer this

Choose this endpoint when you need standardized LOINC identifiers for laboratory or clinical observation terms — particularly for FHIR mapping, HL7 interoperability, research dataset annotation, or EHR integration. Prefer it over free-text clinical NLP tools when you specifically need official Regenstrief LOINC codes. Not suitable if you also need reference ranges, units of measure, or clinical interpretation guidance.

## Known failure modes

- Term shorter than 2 or longer than 60 characters returns a validation error
- Max value outside 1-20 range is rejected
- No matches found returns empty result list with total count of 0
- NLM Clinical Tables upstream service unavailable causes a proxy error
- Non-English or highly abbreviated terms may return zero or irrelevant matches

## How this service works

Regenstrief LOINC laboratory and clinical test codes (via NLM Clinical Tables): LOINC number and long common name matching a term, with total match count. Codes and names only, no units or reference ranges. Up to 20 per call.

## Output

Returns a list of up to 20 LOINC entries, each containing a LOINC number (e.g. '4548-4') and its long common name (e.g. 'Hemoglobin A1c/Hemoglobin.total in Blood'), along with the total count of matching records in the LOINC database. Does not include units, reference ranges, or clinical context.

## 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": [
      "term"
     ],
     "properties": {
      "max": {
       "type": "string",
       "description": "How many codes, 1 to 20 (default 10)"
      },
      "term": {
       "type": "string",
       "description": "Words to search in LOINC names, 2 to 60 characters"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/loinc-laboratory-code-lookup-e6b3e556/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.healthtravel-api.workers.dev](https://www.zero.xyz/host/api.healthtravel-api.workers.dev/llms.txt)