LOINC Search API

Search Regenstrief's LOINC database for laboratory and clinical observation codes.

Endpoint

GET /v1/loinc/search

Quick Start

Node.js

import { Fhirfly } from "@fhirfly-io/terminology";

const client = new Fhirfly({ apiKey: "YOUR_API_KEY" });

// Search for glucose tests in chemistry
const results = await client.loinc.search({
  q: "glucose",
  class: "CHEM"
});

console.log(`Found ${results.total} codes`);
for (const item of results.items) {
  console.log(`${item.code}: ${item.display_name}`);
}

Parameters

Text Search

At least one text search parameter is required.

Parameter	Description	Example
`q`	General text search	`q=hemoglobin`
`name`	Search display name	`name=glucose`
`component`	Search component (analyte)	`component=sodium`

Filters

Parameter	Type	Description	Example
`class`	string	LOINC class	`CHEM`, `HEM/BC`
`system`	string	Specimen system	`Ser/Plas`, `Urine`
`property`	string	Property measured	`MCnc`, `SCnc`
`scale`	string	Scale type	`Qn`, `Ord`, `Nom`
`method`	string	Method used	`Automated count`
`order_obs`	string	Order/Observation	`Both`, `Order`, `Observation`
`status`	string	LOINC status	`ACTIVE`, `DEPRECATED`

Pagination & Response

Parameter	Default	Max	Description
`limit`	20	100	Results per page
`page`	1	100	Page number
`shape`	compact	—	`compact`, `standard`, `full`

Example Response

{
  "facets": {
    "class": {
      "CHEM": 169
    },
    "order_obs": {
      "Both": 131,
      "Observation": 38
    },
    "scale": {
      "Qn": 154,
      "Ord": 7,
      "Nom": 2
    },
    "system": {
      "Ser/Plas": 19,
      "Urine": 22,
      "Bld": 10
    }
  },
  "has_more": true,
  "items": [
    {
      "class": "CHEM",
      "code": "51595-7",
      "component": "Glucose",
      "display_name": "Glucose, Stool",
      "shortname": "Glucose Stl Ql"
    },
    {
      "class": "CHEM",
      "code": "2349-9",
      "component": "Glucose",
      "display_name": "Glucose, Urine",
      "shortname": "Glucose Ur Ql"
    }
  ],
  "limit": 2,
  "meta": {
    "legal": {
      "attribution_required": true,
      "citation": "LOINC from Regenstrief Institute. Accessed 2026-01-28 via FHIRfly.",
      "license": "regenstrief_license",
      "source_name": "LOINC",
      "terms_of_use": "https://loinc.org/license/"
    }
  },
  "page": 1,
  "total": 169,
  "total_capped": false
}

Use Cases

Find Blood Chemistry Tests

Node.js

const results = await client.loinc.search({
  q: "sodium",
  class: "CHEM",
  system: "Ser/Plas"
});

Find Urinalysis Tests

Node.js

const results = await client.loinc.search({
  class: "UA",
  system: "Urine",
  order_obs: "Both"
});

Find Quantitative Tests

Node.js

// Qn = Quantitative (numeric result)
const results = await client.loinc.search({
  component: "hemoglobin",
  scale: "Qn"
});

Find Orderable Tests

Node.js

const results = await client.loinc.search({
  q: "complete blood count",
  order_obs: "Order"
});

LOINC Classes

Common LOINC classes:

Class	Description
`CHEM`	Chemistry
`HEM/BC`	Hematology/Blood Cell Count
`UA`	Urinalysis
`MICRO`	Microbiology
`SERO`	Serology
`COAG`	Coagulation
`DRUG/TOX`	Drug/Toxicology

Scale Types

Scale	Description
`Qn`	Quantitative (numeric)
`Ord`	Ordinal (ordered categories)
`Nom`	Nominal (unordered categories)
`Nar`	Narrative (free text)
`Doc`	Document

LOINC search returns these facets:

Facet	Description
`class`	Distribution by LOINC class
`system`	Distribution by specimen system
`scale`	Distribution by scale type
`order_obs`	Distribution by order/observation

License Note

LOINC requires attribution. The meta.legal field includes:

attribution_required: true
Link to LOINC license terms

Required Scope

loinc.search

LOINC Search API

Endpoint

Quick Start

Parameters

Text Search

Filters

Example Response

Use Cases

Find Blood Chemistry Tests

Find Urinalysis Tests

Find Quantitative Tests

Find Orderable Tests

LOINC Classes

Scale Types

Facets

License Note

Required Scope

See Also

LOINC Search API

Endpoint

Quick Start

Parameters

Text Search

Filters

Pagination & Response

Example Response

Use Cases

Find Blood Chemistry Tests

Find Urinalysis Tests

Find Quantitative Tests

Find Orderable Tests

LOINC Classes

Scale Types

Facets

License Note

Required Scope

See Also

Cookie Preferences