England Pathology and Laboratory Medicine (PaLM) Technical Framework
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Terminology

Tests and Results

Item HL7 v2 FHIR Code system Notes
Result (what was measured) OBX-3 Observation.code SNOMED CT UK Edition - PaLM observable entities The DAPB4101 / NHS England PaLM codes. Example: 1022431000000105 Haemoglobin estimation
      LOINC (second coding) Optional, where known. Example: 718-7
Test group / test ordered or reported OBR-4 ServiceRequest.code, test group Observation.code, DiagnosticReport.code (one test) SNOMED CT UK - PaLM Requestable Tests (refset 1853561000000109) The England equivalent of the National Genomic Test Directory and NICIP - see below
Report type - DiagnosticReport.code, Composition.type SNOMED CT, LOINC 721981007 Diagnostic studies report (NHS England), LOINC 11502-2 Laboratory report
Units OBX-6 valueQuantity.code UCUM Example: 10*9/L, g/L, mmol/mol
Coded result OBX-5 (CWE) valueCodeableConcept SNOMED CT Organisms, qualifiers (Positive, Not detected)
Specimen type SPM-4 Specimen.type SNOMED CT specimen Example: 119297000 Blood specimen
Body site SPM-8 Specimen.collection.bodySite SNOMED CT body structure  
Discipline OBR-24 DiagnosticReport.category HL7 v2 table 0074 Example: HM haematology, CH chemistry, MB microbiology

The SNOMED CT codes in this guide were checked against the UK Edition on tx.fhir.org (4 November 2026). Validation in this guide uses the SNOMED CT UK Edition (http://snomed.info/sct/83821000000107), set in the expansion parameters.

Requestable Tests (PaLM Procedures)

Genomics has the National Genomic Test Directory and imaging has NICIP. For laboratory medicine the national list of tests that can be requested is the SNOMED CT UK Edition Pathology and laboratory medicine procedure simple reference set (1853561000000109) - the PaLM requestables, modelled as SNOMED CT procedures. Results are the PaLM reportables, the observables refset 1853551000000106 (and the older Pathology Bounded Code List 999002881000000100).

  Genomics Imaging Laboratory medicine
National list of requestable tests National Genomic Test Directory (code system, with eligibility criteria) NICIP (code system, mapped to SNOMED CT and OPCS) PaLM procedure refset 1853561000000109 (SNOMED CT subset - no national directory of who offers what, or eligibility)
In this guide - - PaLM Requestable Tests, preferred for the palmProcedure slice of Laboratory Order code and the snomedCT slice of Laboratory Report code (Laboratory Report Codes)
UK Core - - UKCore-PathologyAndLaboratoryMedicineProcedures (same refset), preferred for UKCore-ServiceRequest-Lab.code and UKCore-Observation-Group-Lab.code

Each laboratory keeps its own test catalogue (local codes, profiles, eligibility) and maps it to PaLM. In HL7 v2 send the PaLM code in OBR-4 CWE-1 to CWE-3 and the laboratory's code as the alternate (CWE-4 to CWE-6).

Earlier national catalogues - the National Laboratory Medicine Catalogue (NLMC, Royal College of Pathologists) and the UK Unified Test List (44991000237108, retired in UK Core) - are replaced by PaLM.

The PaLM Requestable Tests value set lists the 358 members of the refset in the UK Edition of 2 July 2025. They are listed, rather than given as a refset rule, because the UK Edition on tx.fhir.org (April 2023) does not yet contain the refset. They were expanded on CSIRO's public Ontoserver by scripts/palm_valueset.py, which can be re-run for a new release.

PaLM to LOINC (illustrative)

HL7 Europe Laboratory, which this guide's profiles derive from, prefers LOINC: ServiceRequest.code is bound to lab-orderCodes-eu-lab (LOINC ORDER_OBS = Order or Both) and Observation.code to lab-obsCode-eu-lab, which includes lab-obsCode-loinc-eu-lab. A map from PaLM to LOINC lets England orders and reports also carry the LOINC code, as a second coding.

palm-procedure-to-loinc shows what a map from the PaLM requestables to LOINC order codes could look like, for the tests in the NHS England examples:

PaLM requestable (SNOMED CT UK) LOINC Equivalence Why
26604007 Full blood count 57021-8 CBC W Auto Differential panel - Blood inexact Panel members differ
252167001 Urea and electrolytes 24321-2 Basic metabolic 2000 panel - Serum or Plasma inexact No LOINC U&E panel
26958001 Hepatic function panel 24325-3 Hepatic function 2000 panel - Serum or Plasma inexact Panel members differ
271244005 Measurement of serum lipid level 24331-1 Lipid 1996 panel - Serum or Plasma inexact Panel members differ
135842001 Serum C reactive protein level 1988-5 C reactive protein [Mass/volume] in Serum or Plasma wider LOINC is serum or plasma
371981000000106 Hb A1c measurement - IFCC standardised 59261-8 Hemoglobin A1c/Hemoglobin.total standardized per IFCC-RMP for CDT in Blood equivalent  
47758006 Hepatitis B surface antigen measurement 5195-3 Hepatitis B virus surface Ag [Presence] in Serum narrower LOINC gives scale and specimen
700152009 Human papilloma virus screening 82675-0 HPV 16+18+31+…+68 DNA [Presence] in Cervix by NAA with probe detection narrower LOINC names the types and method
113076002 Glucose tolerance test 72171-2 Glucose tolerance 2 hours panel - Serum or Plasma narrower The 2 hour (75 g) test
401324008 Urinary microscopy, culture and sensitivities 50554-5 microscopy, 630-4 culture, 29576-6 susceptibility narrower (each) No single LOINC order code

Equivalence is the LOINC code relative to the PaLM code. LOINC codes were checked on tx.fhir.org (LOINC 2.83, 4 November 2026).

Coding Systems in HL7 v2

CWE-3 (and CWE-6) name the coding system. Map them to FHIR Coding.system:

CWE-3 Coding system FHIR system
SCT SNOMED CT http://snomed.info/sct
LN LOINC http://loinc.org
UCUM UCUM http://unitsofmeasure.org
I10 ICD-10 http://hl7.org/fhir/sid/icd-10
HL7nnnn HL7 v2 table nnnn http://terminology.hl7.org/CodeSystem/v2-nnnn
L (or a registered local name) Local laboratory code A URI agreed per laboratory, for example https://fhir.<trust>.nhs.uk/CodeSystem/lims-test

SNM3 (used in some DHCW examples) is SNOMED 3 / SNOMED International in HL7 table 0396; for SNOMED CT use SCT.

Identifier Systems

Identifier HL7 v2 FHIR Identifier.system
NHS Number PID-3 ^^^NHS^NH https://fhir.nhs.uk/Id/nhs-number
ODS organisation code MSH-4, MSH-6, XON-10 https://fhir.nhs.uk/Id/ods-organization-code
ODS site code PL, XON-10 https://fhir.nhs.uk/Id/ods-site-code
GMC number XCN-9 GMC https://fhir.hl7.org.uk/Id/gmc-number
GP (GMP) code XCN-9 GMP https://fhir.hl7.org.uk/Id/gmp-number
NMC number XCN-9 NMC https://fhir.hl7.org.uk/Id/nmc-number
HCPC number XCN-9 HCPC https://fhir.hl7.org.uk/Id/hcpc-number

HL7 v2 Tables

ConceptMaps from HL7 v2 tables to FHIR (indicative, based on the HL7 v2-to-FHIR IG):

Units

UCUM SHALL be used in FHIR and SHOULD be used in HL7 v2 (OBX-6 CWE-1 the UCUM code, CWE-3 UCUM). Common laboratory conversions:

Written UCUM
x10^9/L (HL7 v2 x10\S\9/L) 10*9/L
x10^12/L 10*12/L
g/L g/L
L/L L/L
fL fL
pg pg
mmol/L mmol/L
mmol/mol (HbA1c) mmol/mol
umol/L umol/L
mL/min/1.73m2 (eGFR) mL/min/{1.73_m2}
% %