HL7 Europe Laboratory Report, published by HL7 Europe. This guide is not an authorized publication; it is the continuous build for version 2.0.1-ci built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/hl7-eu/laboratory/ and changes regularly. See the Directory of published versions

Implementation notes

Implementation of laboratory panels

The current version of the HL7 Europe Laboratory Report Implementation Guide describes the use of Observations (with hasMember references) and a single instance of DiagnosticReport to support test panels and batteries (e.g. a Full Blood Count) rather than using DiagnosticReport as the grouping mechanism. We believe that the Observation hasMember approach offers a more flexible and intuitive method than using DiagnosticReport(s) for test groups, especially for complex reports such as example included in the base FHIR R4 specification:

Diagnosticreport-example-ghp.xml - FHIR v4.0.1 (hl7.org)

Implementation of reflex tests

An optional R5 extension of the observation (Observation.triggeredBy-r5) has been pre-adopted in the current version of the HL7 Europe Laboratory Report Implementation Guide. We recommend to use this extension for implementation of the so-called reflex tests, i.e. additional test cases in which more than one test could be used to fulfil a given requirement (order or panel). In such case Observation.triggeredBy-r5.type should be set to #reflex.

Exclusive reference-range bounds

FHIR R4 represents Observation.referenceRange.low and Observation.referenceRange.high as SimpleQuantity, which cannot carry a comparator. This guide pre-adopts the R6 solution through two modifier extensions on Observation.referenceRange: lowComparator and highComparator. Use lowComparator with > or >=, and highComparator with < or <=, when the reference-range bound must be explicitly stated. In particular, use > and < for exclusive bounds.

This is a temporary R4 solution. FHIR R6 changes the reference-range bounds to Quantity and provides the comparator directly on low and high; implementations should transition to that native representation when adopting R6. These optional extensions have no associated obligations because EHDS does not mandate reference-range comparators.

Representation of the microbiology tests

Microbiology tests are often being performed in consecutive steps, e.g. cultivation, possible quantification and subsequent sensitivity testing to antibiotics. Each analytical step depends on the result of the previous step or steps. Current version of the HL7 Europe Laboratory Report Implementation Guide recommends to use Observation.hasMember reference to express causality of the tests performed by the laboratory as shown in the Microbiology Culture + Susceptibility.

Sharing of previous result values

In some cases laboratory wants to share previous results for the same patient, same test, same method, and same measurement unit. In this case implementers should use supportingInfo extension of the Observation resource. Previous result will be expressed as a separate Observation and linked to current Observation through Observation.supportingInfo element.