SNOMED CT for pathology and laboratory medicine reporting

SNOMED CT is the recognised NHS standard terminology for clinical data entry in electronic health and care records. In addition to representing many different types of clinical information, SNOMED CT provides an interoperable and machine-readable mechanism for sharing pathology data.

In the pathology report sent from laboratories to primary care, the DAPB4101 Pathology and Laboratory Medicine Reporting Information Standard governs the use of SNOMED CT Observable entity concepts to represent pathology and laboratory medicine test result codes.

These reportables are included in 2 reference sets:

Pathology Bounded Code List (PBCL) observables simple reference set – containing reportables currently recorded in GP records.

PaLM (pathology and laboratory medicine) observable entity simple reference set - containing reportables designed to replace PBCL, plus new reportables that represent new lab tests.

The PBCL was originally defined as a subset of Read v2 codes. SNOMED PBCL provides a semantically equivalent set of SNOMED reportables to support the transition from Read to SNOMED CT in primary care.

SNOMED PaLM reportables are more detailed than SNOMED PBCL and conform to well-defined editorial principles. All PaLM reportables are fully modelled; the modelled components logically define each concept and allow for machine processing, enabling clinical decision support, and improved analysis of the data. Thanks to SNOMED CT’s concept model, some of the information about a laboratory test is carried inherently in the terminology, with PaLM reportables carrying defining coded attributes relating to measurable characteristic, substance, specimen, and technique.

In terms of specialisms, PaLM reportables cover:

• clinical biochemistry (also known as chemical pathology)
• haematology
• immunology
• transfusion medicine
• microbiology – this includes bacteriology, virology and serology

Further pathology specialism coverage is currently under review.

Other data elements in the Pathology FHIR Specification (those that supplement SNOMED PaLM reportables) can be populated with different types of SNOMED CT concepts. For example, lab test result values such as Positive (qualifier value) or lab test specimen types such as Venous blood (substance). 

This supports the sharing of atomic, coded data in pathology reports.

In addition to reportables, SNOMED PaLM also provides concepts that represent lab test request codes (requestables). These are single data items in the report identifying the specific test(s) requested. SNOMED CT Procedure concepts are used for this purpose and are included in this reference set:

PaLM (pathology and laboratory medicine) procedure simple reference set.

Example of a SNOMED CT Procedure concept representing the laboratory test request code, showing the modelled components is shown below.

These are known as 'requestables' or 'orderables'.

Visit our Pathology FHIR specification page to see examples of how these SNOMED concepts are structured in the pathology report.

All pathology reporting content is included in the SNOMED CT UK Clinical Edition; RF2 files via the TRUD website, or at the NHS England Terminology Server.