HL7 FHIR Observation API
Clinical measurements, lab results, vital signs
Work with this as data
Every API here is available over the APIs.io API and to AI agents over MCP.
MCP server
One button, every client — Claude, Cursor, VS Code and the rest.
https://apis.io/mcp
Tools for apis
7 MCP tools reach this
find_apisBrowse and filter every API in the catalog.get_api_artifactsOne API's artifacts, grouped by type.get_openapiThe primary OpenAPI for this API.find_similar_apisAPIs that look like this one.apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.
Call it yourself
curl for this page
This API
curl "https://apis.io/api/v1/apis/hl7-fhir-observation-api"
All apis
curl "https://apis.io/api/v1/apis?limit=25"Discovery needs no key. Ratings and market analysis are Pro.
Get an API key
Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.
A second provider on the same verified email joins the account you already have.
OpenAPI Specification
openapi: 3.2.0
info:
title: HL7 FHIR R4 Healthcare Bundle Observation API
description: HL7 FHIR R4 (v4.0.1) RESTful API for healthcare data exchange. Provides access to patient demographics, clinical observations, conditions, medications, encounters, care plans, and diagnostic reports. Implements the FHIR REST specification including CRUD operations, search parameters, history, and batch/ transaction bundles. SMART on FHIR OAuth 2.0 authorization required.
version: 4.0.1
contact:
name: HL7 International
url: https://www.hl7.org/fhir/
license:
name: Creative Commons CC0
url: https://creativecommons.org/publicdomain/zero/1.0/
servers:
- url: https://fhir-server.example.com/fhir/R4
description: FHIR R4 server base URL (replace with actual server URL)
security:
- SMARTonFHIR: []
tags:
- name: Observation
description: Clinical measurements, lab results, vital signs
paths:
/Observation:
get:
operationId: searchObservation
summary: Search observations
description: Searches for Observation resources (lab results, vital signs, surveys). Common use cases include retrieving recent vital signs or lab values for a patient.
tags:
- Observation
parameters:
- name: patient
in: query
schema:
type: string
description: Patient reference (e.g., "Patient/123")
- name: category
in: query
schema:
type: string
description: Observation category (vital-signs, laboratory, social-history, etc.)
- name: code
in: query
schema:
type: string
description: LOINC code or system|code (e.g., "8302-2" for body height)
- name: date
in: query
schema:
type: string
description: Observation date filter (e.g., "ge2024-01-01")
- name: status
in: query
schema:
type: string
enum:
- registered
- preliminary
- final
- amended
- corrected
- cancelled
- name: _count
in: query
schema:
type: integer
default: 20
- name: _sort
in: query
schema:
type: string
default: -date
responses:
'200':
description: Bundle of matching Observation resources
content:
application/fhir+json:
schema:
$ref: '#/components/schemas/Bundle'
/Observation/{id}:
get:
operationId: readObservation
summary: Read an observation
description: Returns a specific Observation resource by its logical ID.
tags:
- Observation
parameters:
- name: id
in: path
required: true
schema:
type: string
responses:
'200':
description: Observation resource returned
content:
application/fhir+json:
schema:
$ref: '#/components/schemas/Observation'
'404':
description: Observation not found
components:
schemas:
Observation:
type: object
description: Measurements and simple assertions about a patient or other subject
properties:
resourceType:
type: string
enum:
- Observation
id:
type: string
meta:
$ref: '#/components/schemas/Meta'
status:
type: string
enum:
- registered
- preliminary
- final
- amended
- corrected
- cancelled
- entered-in-error
- unknown
category:
type: array
items:
$ref: '#/components/schemas/CodeableConcept'
code:
$ref: '#/components/schemas/CodeableConcept'
subject:
$ref: '#/components/schemas/Reference'
encounter:
$ref: '#/components/schemas/Reference'
effectiveDateTime:
type: string
format: date-time
issued:
type: string
format: date-time
valueQuantity:
$ref: '#/components/schemas/Quantity'
valueCodeableConcept:
$ref: '#/components/schemas/CodeableConcept'
valueString:
type: string
interpretation:
type: array
items:
$ref: '#/components/schemas/CodeableConcept'
note:
type: array
items:
type: object
properties:
text:
type: string
component:
type: array
items:
type: object
properties:
code:
$ref: '#/components/schemas/CodeableConcept'
valueQuantity:
$ref: '#/components/schemas/Quantity'
required:
- resourceType
- status
- code
Quantity:
type: object
properties:
value:
type: number
comparator:
type: string
enum:
- <
- <=
- '>='
- '>'
unit:
type: string
system:
type: string
format: uri
code:
type: string
CodeableConcept:
type: object
properties:
coding:
type: array
items:
$ref: '#/components/schemas/Coding'
text:
type: string
Meta:
type: object
properties:
versionId:
type: string
lastUpdated:
type: string
format: date-time
profile:
type: array
items:
type: string
format: uri
tag:
type: array
items:
$ref: '#/components/schemas/Coding'
Bundle:
type: object
description: A container for a collection of FHIR resources
properties:
resourceType:
type: string
enum:
- Bundle
id:
type: string
type:
type: string
enum:
- document
- message
- transaction
- transaction-response
- batch
- batch-response
- history
- searchset
- collection
total:
type: integer
description: Total number of matches (for searchset bundles)
link:
type: array
items:
type: object
properties:
relation:
type: string
enum:
- self
- first
- previous
- next
- last
url:
type: string
format: uri
entry:
type: array
items:
type: object
properties:
fullUrl:
type: string
format: uri
resource:
type: object
description: FHIR resource (any type)
search:
type: object
properties:
mode:
type: string
enum:
- match
- include
- outcome
score:
type: number
request:
type: object
properties:
method:
type: string
enum:
- GET
- HEAD
- POST
- PUT
- DELETE
- PATCH
url:
type: string
response:
type: object
properties:
status:
type: string
location:
type: string
required:
- resourceType
- type
Coding:
type: object
properties:
system:
type: string
format: uri
description: Identity of the terminology system (e.g., "http://loinc.org", "http://snomed.info/sct")
version:
type: string
code:
type: string
display:
type: string
userSelected:
type: boolean
Identifier:
type: object
properties:
use:
type: string
enum:
- usual
- official
- temp
- secondary
- old
type:
$ref: '#/components/schemas/CodeableConcept'
system:
type: string
format: uri
value:
type: string
Reference:
type: object
properties:
reference:
type: string
description: Relative or absolute URL (e.g., "Patient/123")
type:
type: string
format: uri
identifier:
$ref: '#/components/schemas/Identifier'
display:
type: string
securitySchemes:
SMARTonFHIR:
type: oauth2
description: SMART on FHIR OAuth 2.0 authorization
flows:
authorizationCode:
authorizationUrl: https://auth.example.com/authorize
tokenUrl: https://auth.example.com/token
scopes:
patient/Patient.read: Read patient data
patient/Observation.read: Read observations
patient/Condition.read: Read conditions
patient/MedicationRequest.read: Read medication requests
patient/Encounter.read: Read encounters
launch/patient: Patient context launch
openid: OpenID Connect identity
externalDocs:
description: HL7 FHIR R4 Specification
url: https://www.hl7.org/fhir/R4/