NLM ICD-10-CM Clinical Tables API

National Library of Medicine · Health

Health No Auth Free & Open Healthcare Life Sciences ICD-10-CM Diagnosis Codes Medical Coding

NIH/NLM hosted ICD-10-CM diagnosis code search API. Returns matching codes and descriptions for clinical diagnosis coding. Updated annually with official CMS releases. No authentication required.

Authentication

No authentication requiredFree to use with no key needed.

Sample Requests

GET Search ICD-10-CM codes

Search ICD-10-CM diagnosis codes by code prefix or description text

https://clinicaltables.nlm.nih.gov/api/icd10cm/v3?df=code,name&sf=code,name&terms=E11&maxList=10

Hover any highlighted part to learn what it does

curl -X GET "https://clinicaltables.nlm.nih.gov/api/icd10cm/v3?df=code%2Cname&sf=code%2Cname&terms=E11&maxList=10"

import requests
params = {
    "df": "code,name",
    "sf": "code,name",
    "terms": "E11",
    "maxList": "10"
}
response = requests.get(
    "https://clinicaltables.nlm.nih.gov/api/icd10cm/v3",
    params=params,
)
print(response.json())

const url = new URL('https://clinicaltables.nlm.nih.gov/api/icd10cm/v3');
url.searchParams.set('df', 'code,name');
url.searchParams.set('sf', 'code,name');
url.searchParams.set('terms', 'E11');
url.searchParams.set('maxList', '10');

const response = await fetch(url); 
const data = await response.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
)

func main() {
	baseURL, _ := url.Parse("https://clinicaltables.nlm.nih.gov/api/icd10cm/v3")
	q := baseURL.Query()
	q.Set("df", "code,name")
	q.Set("sf", "code,name")
	q.Set("terms", "E11")
	q.Set("maxList", "10")
	baseURL.RawQuery = q.Encode()
	targetURL := baseURL.String()
	req, _ := http.NewRequest("GET", targetURL, nil)

	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	fmt.Println(string(body))
}

require "net/http"
require "json"

uri = URI("https://clinicaltables.nlm.nih.gov/api/icd10cm/v3")
uri.query = URI.encode_www_form({
  "df" => "code,name",
  "sf" => "code,name",
  "terms" => "E11",
  "maxList" => "10"
})

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"

req = Net::HTTP::Get.new(uri)

res = http.request(req)
puts JSON.parse(res.body)

<?php
$url = "https://clinicaltables.nlm.nih.gov/api/icd10cm/v3?" . http_build_query([
    "df" => "code,name",
    "sf" => "code,name",
    "terms" => "E11",
    "maxList" => "10"
]);
$opts = ["http" => [
    "method" => "GET",
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));

Postman Setup Guide

Get Postman ↗

No API key required — open NIH service
In Postman, GET https://clinicaltables.nlm.nih.gov/api/icd10cm/v3/search
Add query params: sf=code,name and df=code,name and terms={your search}
Use maxList to control number of results returned
Response is an array: [total, codes[], null, descriptions[]]

What can you build with NLM ICD-10-CM Clinical Tables API?

NLM ICD-10-CM Clinical Tables API is a Health API. Developers commonly use health APIs for:

accessing medical reference data and drug information
building patient-facing health tracking apps
integrating with EHR and telemedicine platforms
looking up ICD codes and clinical terminology
powering wellness and fitness applications

No authentication required. This API is open — no signup or key needed. Ideal for quick prototypes and public-facing features. NLM ICD-10-CM Clinical Tables API is free to use, making it a low-risk choice to experiment with.

New to APIs? Read our beginner's guide

Open documentation ↗