Implementation guide for interoperable medicines

Resource validation errors

Where FHIR resource validation issues arise during processing of consumer requests, provider systems MUST utilise one the following error details:

HTTP code	Issue type	Error code	Error message
`422`	invalid	`INVALID_RESOURCE`	Submitted resource is not valid.
`422`	invalid	`INVALID_PARAMETER`	Submitted parameter is not valid.
`422`	invalid	`REFERENCE_NOT_FOUND`	Referenced resource not found.

Detailed diagnostic information MUST be supplied when erroring on the codes above.

INVALID_PARAMATER would be used in the following, or similar, scenarios:

An invalid date / time value specified in a custom operation parameter.

INVALID_RESOURCE would be used in situations such as the following:

The resource failed structural validation
A resource failed to be procesed because of a FHIR constraint, or other rule application, where the error is not already covered by other error codes

REFERENCE_NOT_FOUND describes a scenario where a consumer POSTs a FHIR resource which contains a FHIR reference that cannot be found.

Example: Reference not found

For example, if a MedicationRequest referenced a Practitioner resource that could not be found or resolved by the server. The following error details would be returned:

{
    "resourceType": "OperationOutcome",
    "meta": {
        "profile": [
            "https://fhir.nhs.uk/StructureDefinition/NHSDigital-OperationOutcome"
        ]
    },
    "issue": [
        {
            "severity": "error",
            "code": "invalid",
            "details": {
                "coding": [
                    {
                        "system": "https://simplifier.net/guide/NHSDigital/NHSDigital-OperationOutcome-Codes",
                        "code": "REFERENCE_NOT_FOUND",
                        "display": "FHIR reference not found"
                    }
                ]
            },
            "diagnostics": "Referenced Practitioner resource not found"
        }
    ]
}