This page is part of the US Prescription Drug Monitoring Program (PDMP) (v1.0.0: STU1) based on FHIR (HL7® FHIR® Standard) R4. This is the current published version in its permanent home (it will always be available at this URL). For a full list of available versions, see the Directory of published versions

Conformance Expectations

Handling Missing Data

In Must Support Elements

Unknown Reason. If the PDMP Responder system does not have data for a Must Support data element, and the reason for absence is unknown:

• The PDMP Responder system responding to a query SHALL NOT include the element in the resource.

• The PDMP Requester system SHALL interpret missing data elements within resource instances as data not present in the PDMP Responder system.

Known Reason. In situations where information on a particular data element is missing and the PDMP Responder knows the precise reason for the absence of data:

• The PDMP Responder system SHALL send the reason for the missing information using values (such as nullFlavors) from the value set where they exist or using the dataAbsentReason extension. (See next section)

• The PDMP Requester system SHALL be able to process resource instances containing data elements asserting missing information.

In Required Elements

If the source system does not have data for a required data element (in other words, where the minimum cardinality is greater than 0), participants must follow the rules below.

Non-Coded Data Elements. Use the FHIR DataAbsentReason Extension with the code, unknown, which means the value is expected to exist but is not known.

Coded Data Elements

• Example, preferred, or extensible binding strengths

  • If the source systems has text but no coded data, only the text element is used.
  • If there is neither text nor coded data, use the appropriate “unknown” concept code from the value set if available
  • If the value set does not have the appropriate “unknown” concept code, use “unknown” from the DataAbsentReason Code System

• Required binding strength

  • Use the appropriate “unknown” concept code from the value set, if available.
  • In cases where the PDMP Responder does not know the correct code, and the value set lacks an appropriate "unknown" code, it SHALL respond to a query for the resource with an OperationOutcome accompanied by a 404 HTTP error code.

  For example, the following status elements do not contain an “unknown” concept code–and so, the element cannot be populated as unknown:

  • AllergyIntolerance.clinicalStatus
  • Condition.clinicalStatus
  • DocumentReference.status