Letter in response to: John W Honour. Standardization of steroid tests and implications for the endocrine community. Annals of Clinical Biochemistry,Vol. 54(6) 618–630

The underlying message that Dr Honour makes in his editorial is that clinicians and laboratories need to be aware of the specificity and calibration of their assays. This is a message that the United Kingdom National External Quality Assurance Scheme (UK NEQAS) has been making for some time, and indeed continues to make. This is uncontroversial. We are glad that someone out there agrees with us. Where we do disagree with the author is the inaccurate assertion that EQA providers have ‘failed for decades’ to put pressure on assay suppliers. The uncomfortable truth is that it is laboratories that make decisions on which assay system they use; EQA providers cannot make that decision on their behalf.

Anyone who has read a UK NEQAS report or Annual Review will be in no doubt of the strong message that is continually and consistently being made.

As an example, if we were to consider serum Cortisol, how does UK NEQAS assess laboratory performance? We use unprocessed endogenous serum as our material, except when we are assessing recovery, and we use a field method Mass Spectrometry (FM-MS) method mean as the target. We use this target for all laboratories whether they use immunoassay or FM-MS. We validate this mean by periodically comparing the target to a candidate reference method. ¹

For several analytes, we have shown that in recent years the overall consensus mean was not a valid target and we took active measures to replace it with something better. In September 2011, we showed, by providing an additional personalized report for every laboratory in the Scheme, what their performance would have been had if we used this ‘best estimate of the truth’ as target for Cortisol, Urinary Free Cortisol (UFC), Androstenedione and for Testosterone in a female matrix. Laboratories and manufacturers alike could be in no doubt as to what their performance actually was. Over the years, we made similar periodic, personalized ‘What-if’ reports showing what each and every laboratory’s performance actually was when an FM-MS mean, and not the all-laboratory trimmed mean (ALTM), was used as target. We gave advanced warning that we would be making this scientifically valid change which was implemented in April 2017.

The data generated through the UK NEQAS for Steroid Hormones scheme, along with user feedback, assisted in the push for the development of the Roche Generation II Cortisol assay. Data displayed on routine UK NEQAS for Steroid Hormones reports and commentaries since the introduction of the new assay has clearly shown a marked improvement in method performance. As an example of our active intervention in such matters, participants will be aware that Birmingham Quality have contacted users of the Roche Generation I Cortisol assay pointing out the difference between the two assays and advised that they review their methods.

UK NEQAS for Steroid Hormones not only challenges analytical performance based on methodology. Other examples of added value include cross-reactivity interference studies and areas of special clinical concern. The cross-reactivity of Prednisolone was reported in December 2016 whilst the most recent Prednisone experiment was carried out in August 2017 and which is currently being written up.

I think the UK NEQAS for Steroid Hormones can rightly be proud of its approach to pushing for better methodologies to make a genuine impact on improving patient care.