HrmContentChecksum Naming system

Status: draft · 1.26.0 · JSON

A content digest of a report ingested from Health Report Manager, carried on DiagnosticReport.identifier. THE VALUE IS COMPUTED, NOT ISSUED: it is a SHA-256, lower-case hexadecimal, over the bytes of the first presentedForm attachment -- the report content, UTF-8 encoded where the message carried text and verbatim where it carried a binary document -- taken before the original message file is attached as a second presentedForm entry, so it covers the report and not the delivery envelope. Two unrelated reports with byte-identical content carry the same value, so it MUST NOT be used as a business identifier, a reference target, or a match key between systems. WHAT IT IS FOR: distinguishing a re-send from a revision once a report has already been matched on its other identifiers. IT IS NOT AN INTEGRITY GUARANTEE -- nothing re-verifies it against the attachment after ingest, so neither a match nor a mismatch is evidence about authenticity; Attachment.hash is the element for that question. MIGRATION: Nexus EMR writes this system today as http://services.well.com/fhir/identifier/hrm-content-checksum (FHIR-372), an address this specification does not publish; it is live in stored Identifier.system values and in code, and is under migration to the URI declared here. Write the URI declared here; expect both until the migration completes.

Type	Value	Preferred
uri	../NamingSystem/hrm-content-checksum	true
uri	http://services.well.com/fhir/identifier/hrm-content-checksum	false