For a full list of available versions, see the Directory of published versions

3.2. Conformance Rules

FHIR is a general-purpose specification and does not require implementers to support specific resources, operations, search parameters, or capabilities unless those requirements are defined by an implementation guide. To achieve consistent PCR contribution interoperability, implementers must make aligned decisions about the FHIR capabilities, contribution operations, resource profiles, and message behaviours their systems will support. FHIR uses the CapabilityStatement resource to define the actual or expected capabilities of a system.

PCR FHIR contribution resources, data types, and message representations shall conform to the HL7 FHIR R4 conformance rules and to the additional contribution-specific constraints defined in this implementation guide. Data elements defined in resources and data types include conformance properties such as cardinality, Is-Modifier, and MustSupport, which together define implementation obligations for submitting, validating, and processing PCR contribution transactions.

3.2.1. MustSupport Flag

To maximize interoperability for PCR contribution, this implementation guide uses the MustSupport flag to identify elements that contributing systems must understand and, where required by the applicable profile and business rules, populate in the request.

Elements marked MustSupport in a contribution request must be submitted when the data is available and required for the operation. If a request does not contain sufficient data to satisfy PCR minimum contribution requirements, PCR may reject the request and return an error or OperationOutcome.

Elements that are not marked MustSupport in a PCR FHIR contribution request may be ignored by PCR unless otherwise specified by the applicable profile or business rule.

Elements marked MustSupport in PCR responses, including acknowledgement and error response content, must be handled meaningfully by the contributing application, such as by storing response identifiers, recording operational outcomes, and triggering remediation workflows when errors are returned.

3.2.2. Content Type and Encodings

The formal MIME types for FHIR resources are application/fhir+json and application/fhir+xml.

For PCR FHIR contribution, JSON is preferred unless otherwise agreed through onboarding or environment-specific implementation guidance. Clients and servers shall use the correct MIME type for contribution request and response bodies.

• JSON preferred: application/fhir+json
• XML: application/fhir+xml

FHIR uses UTF-8 for request and response bodies.

PCR contribution requests and responses shall explicitly set the character encoding to UTF-8 using the charset parameter of the Content-Type header. Requests may also specify the charset parameter in the Accept header and may use the Accept-Charset header where supported.

3.2.3. HTTP Header Fields

The following HTTP header fields should be defined on the request if the client system is capable of doing so:

3.2.4. Data Formatting

3.2.4.1. Letter Case

PCR preserves submitted demographic information in the format provided by the contributing source, including upper case, mixed case, or mixed formatting.

Contributing systems should apply local data quality rules before submission where standardization is required by the organization.

3.2.4.2. Extended Character Set and French Characters

PCR contribution messages shall use UTF-8 encoding to support extended characters beyond the standard ASCII character set, including French characters and other characters submitted by source systems.

3.2.4.3. Leading and Trailing White Spaces

Contributing systems shall not include leading or trailing white spaces in identifier fields or other structured fields where spacing may affect validation, matching, or downstream processing.

3.2.5. Identifier Policy

The PCR FHIR contribution interface uses Uniform Resource Identifiers (URIs) as the primary mechanism for representing identifier systems and implementation-specific namespaces.

URIs support globally unique identification for patient identifiers, profiles, extensions, value sets, code systems, and local naming systems.

All PCR FHIR URIs shall conform to Ontario Health URI management expectations and shall be implemented in a configurable manner to support environment-specific and future governance changes.