Unified Test List (UTL)

Overview

The Unified Test List (UTL) is a catalogue of SNOMED CT coded laboratory medicine test requests and results intended for use by pathology services and their users across the NHS.

SNOMED CT is the recognised NHS Standard for clinical data entry in electronic health and care records.

Following approval of the DAPB4017: Pathology Test and Results Standard by the Data Alliance Partnership Board in August 2021, the UTL is now formally part of the SNOMED CT UK Edition, with a current status of Draft for Trial Use.

Purpose

UTL replaces the current primary care reporting standard, Pathology Bounded Code List (PBCL), to provide an interoperable and machine-readable mechanism for sharing pathology test results.

A nationally standardised catalogue of reportable items, used in conjunction with FHIR (Fast Healthcare Interoperability Resources) message specification and Units of Measurement (UoM) standards allows pathology results to be recorded consistently and unambiguously and will enable results to be shared seamlessly between different systems within the pathology environment and healthcare organisations.

Agreeing and adhering to the new data standards across Pathology will provide clinicians with better, more detailed information to support clinical decision making in the treatment and care of their patients.

Pathology activities can be broadly divided into 3 key areas

  • Requestables - a clinician requests a test
  • Performables – the activities carried out in a laboratory on receipt of a test request and a sample
  • Reportables - the results of the tests are recorded and sent back to the requester

The SNOMED CT codes (and descriptions) are different for each of these processes. The purpose of the UTL is to code the relevant information of each process in a consistent, repeatable and accurate way that is unambiguous and meaningful to the user.

The first priority of the UTL workstream has been to create codes for reporting results – the reportables process - that is to be used by all systems within the pathology healthcare environment to enable migration from old ‘Read code’ based PBCL to SNOMED CT coding within primary care.

How the UTL differs from PBCL

UTL (SNOMED CT) codes are more detailed than the PBCL(Read) codes and conform to well-defined SNOMED CT editorial principles. The underlying SNOMED CT modelling (attributes) associated with each code can be used by system developers to apply constraints and validation rules to data when entered by users ensuring that meaningful values are assigned to the codes. The underlying modelling can also be used to enable decision support providing additional benefits to clinicians in the treatment of their patients.

More detailed information describing how codes are structured can be found in the SNOMED CT Encoded Unified Test List Editorial Principles.

Benefits of UTL vs PBCL

PBCL coverage only supports the requirements for primary care pathology requests and reporting and whilst PBCL is currently still in use in primary care, the codes are no longer maintained and have been deprecated since 2017 in favour of using internationally recognised SNOMED CT codes.

This means that no new PBCL codes can be created when new tests emerge and the PBCL coverage does not fulfil the full range of tests used in the NHS especially those specific to secondary care. As a result, there is no single coding system in use for reporting pathology data within the NHS. Many clinical and laboratory information systems use different pathology coding standards, including localised codes and different units of measure to report test results, making sharing information difficult.

Standardisation through the implementation of the UTL using SNOMED CT codes (together with other standards such as UOM and FHIR) across the entire pathology environment will enable information to be shared consistently making comparison between tests and results across the healthcare organisations easier and more reliable and reduce the risk of misinterpretation of results.  

The increased granularity of the SNOMED CT codes that make up the UTL also means there is less likelihood that information is lost by using a less detailed code to represent the information. Ultimately, we can expect improved patient care through more readily accessible, detailed and consistent information.

Pathology (UTL) Coverage

The UTL is still being developed to support all specialities within pathology. The initial focus was on developing content to support ‘blood sciences’ (i.e. chemical pathology, also referred to as clinical biochemistry, and haematology with a small sample of virology and immunology and other domains).  This has since been expanded to cover the entire PBCL. For information on expected progression into other specialties please see the Product Roadmap.

Editorial Principles

The SNOMED CT Encoded Unified Test List Editorial Principles provide a detailed guide to the current design of the UTL, describing the format for the clinical terms and the reasoning behind editorial decisions. The editorial guide is underpinned by the SNOMED CT Concept Model for observable entities set out by SNOMED International. Worked examples are included for clarity.

Authoring Process

The Authoring Process document describes the steps taken to produce UTL content and the measures taken to ensure it is robust, unambiguous and clinically safe. It also explains how User Centred Design principles have been incorporated into the process so that end user feedback is taken into account.

UTL Release Files

Here you will find the UTL release files. In addition to the release files themselves, each release package includes a brief summary description alongside links to supporting documentation such as the Product Overview and the Release Format Schema Guide.

UTL Feedback

Join the UTL discussion forum or contact us via our mailbox to provide feedback on the current release.

Feedback on individual concepts within a release can be made by clicking on the HTML link in the release file.