England Pathology and Laboratory Medicine (PaLM) Technical Framework - Local Development build (v0.1.0) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions
Inter-Laboratory Workflow (ILW)
Draft. This implementation guide is a draft for discussion. It is not an
authoritative source and is not endorsed by NHS England, IHE or HL7. Check the cited
sources before using it for implementation.
The IHE PaLM Inter-Laboratory Workflow (ILW) profile covers one laboratory (the
Requester) sub-contracting tests to another (the Subcontractor), and the results
coming back. The Requester stays responsible for the order: it reports the results
(including the subcontracted ones) to the Order Result Tracker.
References
Where ILW Applies in England
- Pathology networks - English pathology services are organised into regional
networks, often hub and spoke: an essential services laboratory at each hospital and
a hub laboratory for non-urgent and specialist work. Where hub and spoke use
different LIMS (or different instances), work moves between them as sub-orders
- Specialist and reference laboratories - tests a laboratory does not offer are
referred to another NHS or independent laboratory, for example specialist
immunology, rare metabolic tests or reference microbiology - often through NPEx
(Labgnostic), see below
- Genomics - a pathology laboratory sending a specimen to a Genomic Laboratory Hub
(see the NW GMSA FHIR IG)
In England laboratory to laboratory requests and results often go through
NPEx, the National Pathology Exchange - now marketed as Labgnostic, provided by
X-Lab Ltd and hosted with The Health Informatics Service (THIS) as a national NHS service since
2010. Each LIMS connects once to the exchange (rather than to every other laboratory), and
the exchange carries the sub-order ([LAB-35](LAB-35.html)) and its results
([LAB-36](LAB-36.html)). The identifiers, codes and content rules on these pages still apply
to what each LIMS sends to and receives from the exchange. Message formats and onboarding are
agreed with the provider (To confirm which HL7 v2 messages and versions NPEx uses).
Process Flow
sequenceDiagram
autonumber
participant OP as Order Placer<br/>EPR / GP system
participant RQ as Requester<br/>referring LIMS
participant SC as Subcontractor<br/>reference LIMS
participant ORT as Order Result Tracker<br/>EPR / GP system
OP ->> RQ: OML^O21 [LAB-1]
RQ ->> RQ: Test not available locally - create sub-order
RQ ->> SC: OML^O21 NW / FHIR Laboratory Order (O21) [LAB-35]
SC -->> RQ: ORL^O22
Note over RQ,SC: Specimen (or aliquot) sent with the sub-order number
SC ->> RQ: ORU^R01 / FHIR Laboratory Result (R01) [LAB-36]
RQ -->> SC: ACK^R01
RQ ->> ORT: ORU^R01 [LAB-3] - including the subcontracted result
Rules
- The Requester is the Order Placer of the sub-order: the sub-order has its own
Placer Order Number (assigned by the Requester) and Filler Order Number (assigned by
the Subcontractor)
- The original order is carried as the parent: HL7 v2 ORC-8 / OBR-29 Parent; FHIR
ServiceRequest.basedOn
- The Subcontractor is the performing laboratory of its results: HL7 v2 OBX-23
Performing Organization Name (with OBX-24 / OBX-25 where the receiving system needs
them); FHIR
Observation.performer. When the Requester forwards these results in
LAB-3 it SHALL keep the Subcontractor as the performer, so the report shows who
did the test (a UKAS accreditation requirement - To confirm the exact clause)
- The patient identifiers in the sub-order are those known to the Requester. A
Subcontractor SHOULD NOT assume an MRN from another trust is meaningful locally;
the NHS Number is the shared identifier
