IE (Ireland) Core Implementation Guide - Local Development build (v0.3.0) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

Must Support

Must Support Definition

For the purposes of the IE Core Implementation Guide, Must Support on any data element SHALL be interpreted as follows:

IE Core Responder (Server)

• The server SHALL be capable of including the data element as part of the query results.
• When data is available, the server SHALL populate the element.
• When data is not available and the element has a minimum cardinality of 0, the server MAY omit the element.
• When data is not available and the element has a minimum cardinality > 0, the server SHALL populate the element with either a valid value or the Data Absent Reason extension.

IE Core Requestor (Client)

• The client application SHALL be capable of processing resource instances containing Must Support data elements without generating an error or causing the application to fail.
• The client application SHOULD be capable of displaying Must Support data elements for human use, or processing them for other purposes (e.g. storing, further processing).
• The client application SHALL NOT modify or remove Must Support elements when updating resources on the server.

HIQA conformance levels

The HIQA draft national standards (September 2026) classify every data element as Mandatory, Required or Optional. IE Core maps them as follows (ADR-001):

HIQA	IE Core	Meaning for a sender
Mandatory	minimum cardinality ≥ 1 and MustSupport	SHALL always be sent
Required	MustSupport	SHALL be sent when the data is available
Optional	allowed, no MustSupport	MAY be sent
Not in the dataset for the use case	0..0 in the use-case profile	SHALL NOT be sent (e.g. religion in a Patient Summary)

Where HIQA marks an element Mandatory only within an optional group (for example the lines of the facility address), IE Core enforces it only when the group is present, or by an invariant. Each case is listed on the HIQA Traceability page.

Mandatory Elements

Mandatory elements (minimum cardinality ≥ 1) SHALL always be present in the resource. If the data is not available:

• Use the Data Absent Reason extension to indicate why the data is absent
• Use a null value where the type allows it

Additional IECDI Requirements

Some elements are marked as "Additional IECDI Requirements". These elements:

• Are not Mandatory or Must Support in the base profile
• Are required for IE Core certification testing
• SHOULD be supported by all implementations where the data is available
• Are included in the formal definition and examples

These are marked in the profile tables with the label ADDITIONAL IECDI.