FHIR Chat · Json Validation

I am getting the following error when validating ServiceRequest resources using the FHIR validator (http://hl7.org/fhir/validation.html#jar): "Unrecognised property '@locationReference'"

However, locationReference is a valid field according to the specification (https://www.hl7.org/fhir/servicerequest-definitions.html#ServiceRequest.locationReference).

Could the FHIR Validator be wrong?

The JSON looks like this:

  "resource": {
    "resourceType": "ServiceRequest",
    ...
    "locationReference": [
      {
        "reference": "Location/{id}"
      }
    ],
    ...
  }

Thank you.

Vassil Peytchev (Oct 27 2021 at 15:51):

If this is the literal JSON, the line "reference": "Location/{id}" should contain the actual location id (e.g. "reference": "Location/33245")

I am not sure if that is the cause of the error, though.

Vanya Yaneva-Cormack (Oct 27 2021 at 15:54):

Thank you for the reply. Yes, the actual json has the correct Location id - I simply redacted it before posting.

Lloyd McKenzie (Oct 27 2021 at 16:37):

In ServiceRequest, 'location' is not a polymorphic type. I.e. its name is not "location[x]" in the spec. That means that the proper element name is just "location" not "locationReference". We only append the type name to an element name when we're replacing a "[x]".

Vanya Yaneva-Cormack (Oct 27 2021 at 17:07):

Thank you for the reply Lloyd.

I tried changing to:

    "location": [
      {
        "reference": "Location/{id}"
      }
    ]

but I am getting a new error: The property reference must be an Object, not a primitive property (at Bundle.entry[0].resource.location[0].reference). Here Bundle.entry[0].resource points to the ServiceRequest.

Could you help me make sense of it?

Lloyd McKenzie (Oct 27 2021 at 17:54):

If you're using R5, then "location" is a CodeableReference, which means you need location.reference.reference before you specify "Location/{id}". If you're trying to do something with R4, make sure you assert the version when you invoke the validator

Alan Pinder (Oct 28 2021 at 11:49):

Lloyd McKenzie said:

In ServiceRequest, 'location' is not a polymorphic type. I.e. its name is not "location[x]" in the spec. That means that the proper element name is just "location" not "locationReference". We only append the type name to an element name when we're replacing a "[x]".

Hi Lloyd, thanks for this answer. I don't think I understood this about the FHIR spec before, and I'm not clear exactly where it does and doesn't apply, apart from polymorphic types.

It doesn't seem intuitive to me, eg in the PatientResource we see nodes like managingOrganization which can only ever be an Organization, but I expected my Patient resource to carry the node managingOrganization. Ditto for generalPractitioner - it's not an [x] although it supports multiple different resources to represent it.

Could you clarify further? The system that is sending us the node 'locationReference' will need this to be clearly understood, I think. before they change their code.

Lloyd McKenzie (Oct 28 2021 at 15:01):

Essentially, the name that you see in the specification is the name that must appear in the instance except when the name ends with [x]. In those cases, you replace the [x] with the name of the type you're instantiating. It's certainly possible that some names will end in the name of a resource - e.g. generalPractitioner. However, there's no guarantee that the type name corresponds to what the element points to or contains. For example, generalPractitioner might be a reference to an Organization.

The issue with your instance was that the ServiceRequest resource defines an element called location. It does not define an element called locationReference. So if you use the latter, it's not going to validate.

Vassil Peytchev (Oct 28 2021 at 15:09):

In R4, there are two elements in the ServiceRequest resource, locationCode and locationReference. In R5, they have been conflated into location as a CodeableReference.

Lloyd McKenzie (Oct 28 2021 at 15:31):

Ah, sorry. I didn't look at R4.

Vassil Peytchev (Oct 28 2021 at 17:37):

So if the resource being validated is from R4, the element name should be locationReference and the validator should be told that the resource contents are following the R4 requirements.