Units of Measure (UoM)

The UoM Project

Product Vision Statement

For producers and consumers of pathology diagnostics within the NHS

Who need safe reliable communication of diagnostic results for both human (clinician + patient) and computer interpretation.

The UoM project will analyse both the current state and future needs for describing units of measure in Pathology, in order to deliver a solution that meets the need for a fully computable pathology message structure, without compromising patient safety or usability for clinicians or patients.

Unlike current practice

The future UoM solution will support the FHIR and UTL projects in delivering a pathology reporting capability that is understandable and processable by computational means, allowing for new healthcare tools and processes to be developed and used safely.


The overall aims of the project are to-

  1. Understand current practice (specifically relating to PMIP messaging and PBCL)
  2. Investigate future requirements, and implementation options
  3. Propose a solution to deliver safe reliable communication of diagnostic results for both human (clinician) and computer interpretation, within the following constraints-
    1. Do not compromise (and if possible improve) usability and clarity for clinicians and patients
    2. Do not compromise (and if possible improve) patient safety
  4. Propose a migration path from the current state to the future solution

Workstream Structure

Stage Delivery Plan (provisional)

A more detailed plan of activities for the next stage of the UoM workstream has been defined. This is subject to approval and is provisional at this point.
UoM Stage Deliverables to 2021-03 v01

Current Status

The next stage of the UoM project was planned to start in Sep/October 2020 but was delayed due to other priorities and is not expected to re-start until after April 2021. A major part of this stage will be creation of a User Reference Group (URG) to help us analyse in detail the issues highlighted during the discovery phase, assess potential solutions etc.

The URG will be most successful if we are able to engage stakeholders with a wide range of skills and expertise. We are actively seeking members with backgrounds in Clinical practice (primary + secondary care), Laboratory practice, Laboratory and NHS Trust IT systems, Software suppliers, Public Health & Screening, Health Science Research, and Patient experience.

If you or someone in your organisation might have relevant knowledge to offer, please contact me- colin.evans@nhs.net to discuss the goals of the URG and how you can contribute to our understanding of the requirements in this space.

Workstream Updates



  • Initial report on UoM requirements and an assessment of LSR and UCUM ["Units of Measure (UoM)" first draft v0.1 April 2018) updated and reformatted for internal review/approval.
  • Report on UoM in Laboratory reporting ("IUG Report- Units of Measure in Pathology Reporting") finalised and ready for approval.
  • Initial mapping of IUG unit codes to UCUM codes completed and has undergone internal clinical review.
  • Updated IUG package with UCUM code mapping and some additional minor technical changes released (IUG v0.2.x).


  • Activity on the UoM workstream has been on hold since approx Sep 2020 because of other priorities in the programme. We hope to restart active work in the first half of 2021.

Requirements & Solutions


  • Report on potential requirements vs. LSR and UCUM (NHS Digital Internal)
  • "e-Poster" presentation on the UK UoM project submitted for display at the SNOMED International Expo 2019 in Kuala Lumpur

Data Model


First draft of UoM data model for internal discussion.

For previous Done / Planned milestones please visit our Newsletter Archive.

Join the Conversation

The forum below is for general questions and discussion about the UoM project itself, and on the broader topic of Units of Measure in Pathology, including support in IT systems and related technologies including FHIR, SNOMED, UCUM and others.

To request access to site general forums please email pathologyandidagnostics@nhs.net

UoM User Reference Group (UoM URG)

The UoM URG is a group of group of stakeholders and subject matter experts that work with us to-

  • Understand clinical, technical and operational requirements
  • Assess available solutions and design options
  • Describe the requirements of stakeholder groups that will be affected by the decisions made
  • Make recommendations on how to address challenges

The Design Issues and Requirements areas, while open to all, are primarily for use by URG members to support the work of the group. If you would like to discuss joining the URG please contact me colin.evans@nhs.net

Collaborative Documents in Draft