SNOMED CT for pathology reporting
SNOMED CT contains a national catalogue of pathology laboratory test request and result codes published in PaLM and PBCL reference sets.
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 request and result data.
Procedure concepts represent laboratory test request codes and Observable entity concepts represent laboratory test result codes.
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 specific pathology laboratory test result codes
- SNOMED CT Procedure concepts to represent the specific laboratory test initially requested (including panels/batteries of tests)
SNOMED CT concepts used in pathology reporting relate to 2 legacy national catalogues of pathology laboratory test codes, the Pathology Bounded Code List (PBCL) and the Unified test List (UTL).
The PBCL was originally, a subset of Read v2* codes for use in laboratory to GP messaging. Semantically equivalent SNOMED CT PBCL concepts were created for migration to SNOMED CT in primary care, and these are contained in the PBCL observables simple reference set.
The UTL was developed in 2018 to replace the PBCL. It started as a code list of descriptions representing pathology laboratory test requests and results with each code carrying a SNOMED CT concept identifier. Following extensive modelling and classification it has since evolved into ‘true’ SNOMED CT and in 2023, the UTL ceased to be published as a standalone terminology product. These concepts are now included in 2 PaLM (pathology and laboratory medicine) reference sets.
SNOMED CT PaLM concepts are more detailed than SNOMED CT PBCL concepts and conform to well-defined editorial principles. All PaLM concepts 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 Observable entities carrying defining coded attributes relating to measurable characteristic, substance, specimen, and technique.
Example of a SNOMED CT Procedure concept representing the laboratory test request code, showing the modelled components. The laboratory test request code is a single data item in the report identifying the specific test(s) requested:
These are known colloquially as 'requestables' or 'orderables'.
The corresponding SNOMED CT Observable entity concept representing the laboratory test result code, showing the modelled components. The laboratory test result code is a single data item in the report identifying the specific test to which a value(s) and interpretation can be assigned:
It’s useful to think of Observable entity concepts as ‘asking a question’. In this context, what is the result of the substance concentration of bicarbonate in urine test?
These are colloquially known as ‘resultables’ or ‘reportables.’
Visit our Pathology FHIR specification page to see examples of how these concepts are structured in the pathology report.
Coverage
In terms of specialisms, SNOMED CT pathology reporting content covers:
- 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.
Being pathology-specific, this content does not cover other specialisms such as genomics and diagnostic imaging.
How to get SNOMED CT
All pathology reporting content is included in the SNOMED CT UK Clinical Edition; RF2 files via the TRUD website, or viewable at the NHS England Terminology Server.
To aid implementation, SNOMED CT pathology reporting content is published in 3 SNOMED CT reference sets (Refsets):
- Pathology Bounded Code List (PBCL) observables simple reference set - containing laboratory test result codes
- PaLM (pathology and laboratory medicine) procedure simple reference set – containing laboratory test request codes
- PaLM (pathology and laboratory medicine) observable entity simple reference set - containing more granular, detailed laboratory test result codes than those in the PBCL Refset
Topography and morphology coding required for secondary reporting for the Cancer Outcomes and Services Data Set is not in scope of the Pathology Reporting Standard. Information about this coding can be found within the NHS Data Model and Dictionary.
Last edited: 23 May 2024 4:10 pm