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Medplum Terminology Services

Medplum provides a layer of functionality to make working with coded values simple. Some of the most common use cases are detailed below to show how these components can fit together.

Binding an input to a set of codes​

To restrict the set of values that can be used with an input, it can be bound to a ValueSet defining which codes are allowed. This enables a typeahead UI, where the user can select from a list of available codes, and type part of the desired concept to filter the list and aid in selection when the set of possible codes is large.

Defining the ValueSet​

First, the ValueSet resource must be uploaded to the Medplum FHIR server, and must contain a url by which to reference it.

{
  "resourceType": "ValueSet",
  "url": "http://example.com/ValueSet/vitals",
  "name": "vitals",
  "title": "Vital Signs",
  "status": "active",
  "compose": {
    "include": [
      {
        "system": "http://loinc.org",
        "concept": [
          { "code": "8310-5", "display": "Body temperature" },
          { "code": "8462-4", "display": "Diastolic blood pressure" },
          { "code": "8480-6", "display": "Systolic blood pressure" },
          { "code": "8867-4", "display": "Heart rate" },
          { "code": "9279-1", "display": "Respiratory rate" }
        ]
      }
    ]
  }
}

Additionally, the URL used to refer to the code system in ValueSet.compose.include.system must actually correspond to a valid CodeSystem resource on the server:

{
  "resourceType": "CodeSystem",
  "url": "http://loinc.org",
  "name": "LOINC",
  "status": "active",
  "content": "example",
  "concept": [
    { "code": "8310-5", "display": "Body temperature" },
    { "code": "8462-4", "display": "Diastolic blood pressure" },
    { "code": "8480-6", "display": "Systolic blood pressure" },
    { "code": "8867-4", "display": "Heart rate" },
    { "code": "9279-1", "display": "Respiratory rate" }
  ]
}

Binding to the Input​

The CodeInput, CodingInput, and CodeableConceptInput React components provide the ability to connect an input field with a ValueSet for typeahead, returning whichever data type is needed by the application.

import { Coding } from '@medplum/fhirtypes';
import { CodingInput } from '@medplum/react';

<CodingInput
  name="vital-sign-code"
  binding="http://example.com/ValueSet/vitals"
  onChange={(c: Coding) => {
    console.log('User selected: ' + c.display + ' (' + c.system + '|' + c.code + ')');
  }}
/>