LOINC MCP Server

A Model Context Protocol server for querying LOINC (Logical Observation Identifiers Names and Codes) terminology through the LOINC Search API.

Available Tools

Related MCP server: OMOPHub MCP Server

Quick Start

Prerequisites

• Python 3.12+

• uv

• A LOINC account (free at loinc.org/join)

Install as a uv tool

git clone https://github.com/robsyc/loinc-mcp && cd loinc-mcp
uv tool install .

Then add to your .cursor/mcp.json or Claude Desktop config:

{
  "mcpServers": {
    "loinc-mcp": {
      "command": "loinc-mcp",
      "env": {
        "LOINC_USERNAME": "your-username",
        "LOINC_PASSWORD": "your-password"
      }
    }
  }
}

Run with uvx

{
  "mcpServers": {
    "LOINC": {
      "command": "uvx",
      "args": ["--from", "git+https://github.com/robsyc/loinc-mcp", "loinc-mcp"],
      "env": {
        "LOINC_USERNAME": "your-username",
        "LOINC_PASSWORD": "your-password"
      }
    }
  }
}

Usage Examples

"Search for LOINC codes related to glucose"

"Get the full details for LOINC code 2339-0"

"Look up the lipid panel 24331-1 and show me its members"

API Details

This server wraps the LOINC Search API:

• Base URL: https://loinc.regenstrief.org/searchapi/

• Auth: HTTP Basic Authentication (LOINC account credentials)

• Endpoints used: /loincs (search) and FHIR /Questionnaire/{code} (panels)

• Rate limiting: 10 requests/second (enforced client-side)

LOINC Class Types

Panel Detection

When get_code is called for a panel (detected via the CLASS field), panel members are automatically fetched from the FHIR Questionnaire endpoint. For survey panels, answer options are included inline with each member.

Development

uv sync --group dev

# Lint
uv run ruff check src/ tests/

# Tests
uv run pytest tests/ -v

# MCP Inspector
LOINC_USERNAME=your-user LOINC_PASSWORD=your-pass uv run fastmcp dev inspector src/loinc_mcp/server.py:mcp

Acknowledgments

• LOINC for the terminology and API

• Regenstrief Institute for maintaining LOINC

• FastMCP for the MCP framework