Usage scenarios

The following are supported usage scenarios for this profile:

• Query for diagnostic results for a patient
• Query for category of diagnostic results (e.g. all cardiology results)
• Record or update a diagnostic result for a patient

Comparison with other national and international specifications

A resource conforming to this profile is conformant to:

• IPA-Observation
• and MAY be conformant to
  • Observation Results (IPS) if patient is supported as Observation.subject.reference and Observation.status is final
  • US Core Observation Clinical Result noting that US Core extensibly binds Observation.code to LOINC and restricts Observation.quantity[x] to UCUM for coded quantity units

Conformance in reverse is not guaranteed, i.e. a resource conforming to International Patient Access, International Patient Summary, or US Core MAY NOT conform to AU Core.

Profile specific implementation guidance

• Observation.category provides an efficient way of supporting system interactions, e.g. restricting searches. Implementers need to understand that data categorisation is somewhat subjective. The categorisation applied by the source may not align with a receiver’s expectations.
• The observations MAY have additional codes that translate or map to the Observation code or category codes. For example:
  • providing a local code
  • providing a more specific code
• The use of coding can vary significantly across systems, client applications need to understand that they may encounter codes they do not recognise and be prepared to handle those resources appropriately. Servers SHOULD populate Observation.code.text and/or Observation.code.coding.display so that client applications can at least display the observation even if the client application does not recognise the code supplied.
• The Observation resource can represent a result using one or both of a single value with Observation.value, or set of results using either Observation.component.value or Observation.hasMember.
  • Although all are marked as must support, servers are not required to support all choices, but they SHALL support at least one of these elements
  • A client application SHALL support both elements
• Observation.identifier may contain the same identifier as in the order or report connecting the resources that are related to a single request fulfilment workflow
• Source system identifiers that identify the business process (order ids and reporting identifiers) MAY be included as AU Local Order Identifier and AU Local Report Identifier to support workflow and deduplication of Observation resources.
  • See guidance on the construction of an identifier on the relevant Identifier profile page and the section on Business Identifiers in AU Base.

Below is an overview of the mandatory and optional search parameters and combined search parameters. FHIR search operations and the syntax used to describe the interactions is described here.

Any search parameter defined in FHIR may be ‘allowed’ by the system unless explicitly marked as “SHALL NOT”. A few items are marked as MAY in this implementation guide to highlight their potential relevance.

Mandatory Search Parameters:

The following search parameters and search parameter combinations SHALL be supported:

1. SHALL support searching using the patient search parameter:
   • SHALL support these _revinclude parameters: Provenance:target
   • SHOULD support chained searching of patient canonical identifier patient.identifier (e.g. patient.identifier=[system|][code])

   GET [base]/Observation?patient={Type/}[id] or optionally GET [base]/Observation?patient.identifier=[system|][code]

   Example:

   1. GET [base]/Observation?patient=5678
   2. GET [base]/Observation?patient.identifier=http://ns.electronichealth.net.au/id/medicare-number|32788511952
   3. GET [base]/Observation?patient.identifier=http://ns.electronichealth.net.au/id/medicare-number|32788511952&_revinclude=Provenance:target
   4. GET [base]/Observation?patient.identifier=http://ns.electronichealth.net.au/id/hi/ihi/1.0|8003608833357361

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient (how to search by reference and how to search by token)

2. SHALL support searching using the combination of the patient and category search parameters:
   • SHALL support these _revinclude parameters: Provenance:target
   • SHOULD support chained searching of patient canonical identifier patient.identifier (e.g. patient.identifier=[system|][code])

   GET [base]/Observation?patient={Type/}[id]&category={system|}[code]

   Example:

   1. GET [base]/Observation?patient=5678&category=http://terminology.hl7.org/CodeSystem/observation-category|survey

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and a category code = survey (how to search by reference and how to search by token)

3. SHALL support searching using the combination of the patient and code search parameters:
   • SHALL support these _revinclude parameters: Provenance:target
   • SHOULD support chained searching of patient canonical identifier patient.identifier (e.g. patient.identifier=[system|][code])
   • SHOULD support multipleOr search on code (e.g.code={system|}[code],{system|}[code],...)

   GET [base]/Observation?patient={Type/}[id]&code={system|}[code]{,{system|}[code],...}

   Example:

   1. GET [base]/Observation?patient=5678&code=http://snomed.info/sct|89240007,http://loinc.org|14683-7,http://loinc.org|85354-9

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and observation code(s). The Observation code parameter searches Observation.code only. (how to search by reference and how to search by token)

4. SHALL support searching using the combination of the patient and category and date search parameters:
   • SHALL support these _revinclude parameters: Provenance:target
   • SHOULD support chained searching of patient canonical identifier patient.identifier (e.g. patient.identifier=[system|][code])
   • SHALL support these date comparators: gt,lt,ge,le
   • SHOULD support multipleAnd search on date (e.g.date=[date]&date=[date]]&...)

   GET [base]/Observation?patient={Type/}[id]&category={system|}[code]&date={gt|lt|ge|le}[date]{&date={gt|lt|ge|le}[date]&...}

   Example:

   1. GET [base]/Observation?patient=5678&category=http://terminology.hl7.org/CodeSystem/observation-category|survey&date=ge2020-01-01T00:00:00Z

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and date and category (how to search by reference and how to search by token and how to search by date)

Optional Search Parameters:

The following search parameters and search parameter combinations SHOULD be supported:

1. SHOULD support searching using the combination of the patient and category and status search parameters:
   • SHALL support these _revinclude parameters: Provenance:target
   • SHOULD support chained searching of patient canonical identifier patient.identifier (e.g. patient.identifier=[system|][code])
   • SHALL support multipleOr search on status (e.g.status={system|}[code],{system|}[code],...)

   GET [base]/Observation?patient={Type/}[id]&category={system|}[code]&status={system|}[code]{,{system|}[code],...}

   Example:

   1. GET [base]/Observation?patient=5678&category=http://terminology.hl7.org/CodeSystem/observation-category|survey&status=final

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and category and status (how to search by reference and how to search by token)

2. SHOULD support searching using the combination of the patient and code and date search parameters:
   • SHALL support these _revinclude parameters: Provenance:target
   • SHOULD support chained searching of patient canonical identifier patient.identifier (e.g. patient.identifier=[system|][code]
   • SHOULD support multipleOr search on code (e.g.code={system|}[code],{system|}[code],...)
   • SHALL support these date comparators: gt,lt,ge,le
   • SHOULD support multipleAnd search on date (e.g.date=[date]&date=[date]]&...)

   GET [base]/Observation?patient={Type/}[id]&code={system|}[code]{,{system|}[code],...}&date={gt|lt|ge|le}[date]{&date={gt|lt|ge|le}[date]&...}

   Example:

   1. GET [base]/Observation?patient=5678&code=http://snomed.info/sct|89240007,http://loinc.org|14683-7,http://loinc.org|85354-9&date=ge2020-01-01T00:00:00Z
   2. GET [base]/Observation?patient.identifier=http://example.org/fhir/mrn|12345&code=http://snomed.info/sct|89240007,http://loinc.org|14683-7,http://loinc.org|85354-9&date=ge2020-01-01T00:00:00Z

   Implementation Notes: Fetches a bundle of all Observation resources for the specified patient and date and observation code(s). SHOULD support search by multiple codes. (how to search by reference and how to search by token and how to search by date)