Evaluation of measurement uncertainty: Where we were and where we are going

Back in 2017 I submitted a series of articles in Pathology in Practice about approaching measurement uncertainty (MU) in medical laboratories. At that time, it was recognised that a framework was needed to simplify the approach of the GUM method;¹ despite CLSI EP29A being available since 2012,² it was not implemented at scale. In late 2019, ISO released a technical specification document in an attempt to provide such a framework – ISO/TS 20914:2019.³ Four years on, uptake both locally in laboratories and internationally in the peer-reviewed literature has shown steady progress. In doing so it has developed our understanding of the concept and allowed us to move onto the next phase of better understanding what it means and how it is used. The progress has been such that the release of the updated ISO15189 accreditation document in late 2022 has referenced the ISO/TS 20914 within the notes to MU clauses.⁴ In September 2023, I was invited to present at the IBMS Congress to discuss these developments.

A reminder of why we assess measurement uncertainty

Rather than only being an accreditation requirement, and one that came to the fore with the advent of laboratories implementing ISO15189, MU has been on laboratory radars for some time. In fact, as far back as 2006⁵ the impact of MU on specific services was being discussed. From this publication there are two quotes that nicely emphasise the importance of MU. Firstly, that MU has various potential benefits for the laboratory and organisation, and secondly MU provides a mechanism for a “better understanding of assay limitations”.⁵