UKAS comes from an engineering background. Although the readings are less important than conforming to the written procedures for obtaining them, UKAS tries its best to practice metrical perfectionism. This might be appropriate for machines but often it is not helpful for biological measurements.
Every competent lab cares deeply about obtaining accurate results. It uses a number of methods to achieve this, including Internal Quality Control (IQC) using known concentrations in samples.
External Quality Assurance (EQA) results from participating laboratories show that deviances occur in the results of different labs examining the same spiked sample. There has been no thorough analysis of historical EQA results to show if accreditation has any benefit to the veracity of results.
Illustrating the importance of clinical interpretation of numerical results, Paul E. Sax, MD says,
“…We all know that patients with very high CD4 counts, who are virologically suppressed, have a lot of variability in the CD4 counts. I’m sure many of you who manage these patients have to explain to patients that their CD4 count could go from 800 to 1000 to 600 to 500 cells/µL. The real clinical importance of that is unknown, and it certainly doesn’t change our management. What about the discordant patients? We all have patients in our practice who are virologically suppressed but fail to get a good CD4 response. How about them?…”
Although labs test the quality of their results daily, UKAS has never been subject to testing of its dogma that quality equals compliance with protocols. Instead it substitutes inspection of its processes by peer inspection bodies in the international cartel.
UKAS demands verification of everything from its victim organisations but has never been subject to verification of its own efficacy.