ValueSet $validate-code

The $validate-code operation checks whether a code is a valid member of a specific ValueSet. Unlike CodeSystem validation (which checks if a code exists anywhere in a code system), ValueSet validation confirms that a code is within the specific subset of codes allowed for a particular use-such as the list of valid allergy severity codes or permitted procedure types.

This is critical for enforcing business rules and data quality, ensuring that clinical data conforms to the specific terminology constraints defined for your application's forms and interfaces.

Use Cases

• Input Validation: Ensure user-selected codes or codes from external systems are valid for specific fields or expected ValueSets before processing
• Constraint Enforcement: Validate that incoming data meets ValueSet-based constraints defined in FHIR profiles or implementation guides like US Core
• Custom Picklist Validation: Verify selections against organization-specific ValueSets that subset larger code systems

Invoke the $validate-code operation

[baseUrl]/ValueSet/$validate-code
[baseUrl]/ValueSet/[id]/$validate-code

Parameters

Name	Type	Description	Required
url	uri	The canonical URL of the ValueSet to validate against	No*
code	string	The code to look up.	No
system	string	The canonical URL of the code system the code belongs to.	No
coding	Coding	Look up via full Coding.	No
codeableConcept	CodeableConcept	Look up multiple related codes.	No
display	string	Additionally validate the given display text	No
abstract	boolean	Whether codes labeled as abstract should be included. Abstract codes represent broad categories or groupings rather than specific concepts, e.g. "Vital Signs"	No

^* If no url is provided, the operation must be invoked on a specific ValueSet instance.

Required Parameters

Although no parameters are strictly required by the operation, at least one of the following must be provided:

• Both code and system parameters (and optionally display)
• The coding parameter
• The codeableConcept parameter with at least one contained coding

Output

The operation returns a Parameters resource containing the validation result.

Name	Type	Description	Required
result	boolean	Whether or not any given coding is included in the ValueSet	Yes
display	string	The display text of the included code	No

Error Responses

Example: Specified ValueSet could not be found by URL (400 Bad Request)

{
    "resourceType": "OperationOutcome",
    "issue": [
        {
            "severity": "error"
            "code": "invalid",
            "details": {
                "text": "ValueSet http://example.com/ValueSet/missing not found"
            },
        }
    ]
}

Examples

Request:

TypeScript

const result = await medplum.post(medplum.fhirUrl('ValueSet', '$validate-code').toString(), {
  resourceType: 'Parameters',
  parameter: [
    { name: 'url', valueUri: 'http://hl7.org/fhir/ValueSet/condition-severity' },
    { name: 'coding', valueCoding: { system: 'http://snomed.info/sct', code: '255604002' } },
  ],
});

cURL

curl 'https://api.medplum.com/fhir/R4/ValueSet/$validate-code' \
  -X POST \
  -H "Content-Type: application/fhir+json" \
  -H "Authorization: Bearer $MY_ACCESS_TOKEN" \
  -d '{"resourceType":"Parameters","parameter":[{"name":"url","valueUri":"http://hl7.org/fhir/ValueSet/condition-severity"},{"name":"coding","valueCoding":{"system":"http://snomed.info/sct","code":"255604002"}}]}'

Response: (200 OK)

{
  "resourceType": "Parameters",
  "parameter": [
    { "name": "result", "valueBoolean": true },
    { "name": "display", "valueString": "Mild (qualifier value)" }
  ]
}

Related

• ValueSet $expand - Expand a value set to see all valid codes
• CodeSystem $validate-code - Validate codes against code systems
• CodeSystem $lookup - Look up details about codes
• Medplum Terminology Guide - Overview of terminology services
• FHIR ValueSet $validate-code - FHIR specification