In the latest (2012) version of ISO 15189, a few key words were dropped from an important sentence about measurement uncertainty. In previous versions, uncertainty was required "where relevant and possible." In the new version, laboratories don't have a choice. They must calculate measurenment uncertainty, even when irrelevant and impractical. The only certainty now about measurement uncertainty is that ISO has made it a commandment. Thou shalt MU!
Uncertainty is an ISO-driven metrological concept. For years, while it has been popular in Europe, uncertainty has been discussed in the US, but never implemented. Now that CLSI has issued its C51A guideline, uncertainty is now official in the US, too. The C51 guideline is worth exploring in detail, for those who seek metrological orthodoxy in their testing processes.
Looking beyond the terminology of Trueness and Uncertainty, Dr. Westgard examines the intended uses and customers of these terms. If we spend our time fighting about Metrological definitions, are we serving the patient?
Trueness. Uncertainty. Accuracy. Precision. Why are there so many definitions for the same terms? Dr. Westgard traces the history of metric concepts in the clinical laboratory. See when and where ISO, IFCC, and CLSI began introducing new terminology into the lab.
Total Error. Trueness. Uncertainty. Can these terms coexist? Under ISO, will defining an allowable error for a test become unacceptable? Will the embrace of ISO accreditation mandate the rejection of all non-ISO-conforming terminology and concepts?
The debate - and the future - is uncertain.