Comment on: Standardization of steroid tests and implications for the endocrine community

The recent editorial describes standardization of laboratory steroid tests but does not address issues relating to metrological traceability and the requirement for traceability of methods for manufacturers as detailed by European Union In Vitro Diagnostics directive, and International Standardization Organization (ISO) ISO17511. Metrological traceability and method specificity are the mainstay of obtaining accurate patient results. More laboratories are now accredited to ISO 15189:2012 which requires evidence of traceability. Additionally, external quality assessment (EQA) organizations that are accredited to ISO17043 are required to use reference measurement targets, where available, as target values for assessment of participant results. The Joint Committee for Traceability in Laboratory Medicine (JCTLM) also actively promotes traceability and has a database of reference materials, reference measurement methods and reference measurement services that includes listings for steroids.

The paragraph relating to EQA programmes suggests that EQA providers are not directly addressing performance of steroid field methods. We believe that this statement is no longer correct; several EQA organizations already provide steroid reference measurement values as part of the assessment of accuracy in their steroid EQA programmes. Poor performance issues relating to metrological traceability or method quality can then be addressed with the manufacturer accordingly.

At Weqas, we have made a large commitment, both financially and in our strategic vision, to develop reference measurement procedures in order to ensure that our EQA samples are provided with accuracy-based reference measurement values using accredited methods where available.

Weqas endocrine programme uses unadulterated individual donations from healthy patient donors. However, due to the large volume of sample required for the isotope dilution gas chromatography mass spectrometry reference method, we have been unable to provide reference values for all our samples. In order to address this issue, we recently changed methodology to a more sensitive isotope dilution liquid chromatography tandem mass spectrometry method that utilizes a much smaller sample volume. This means that reference measurement values for cortisol are available on all samples. Once fully validated, testosterone will also be available on all EQA distributions; progesterone and oestradiol will likewise follow shortly.

Manufacturers of mass spectrometers are beginning to develop systems for steroid analysis that require minimal user intervention, and it is anticipated that these will become more widely used over time. Additionally, the use of two-dimensional high-performance liquid chromatography has led to field steroid liquid chromatography tandem mass spectrometry methods that can provide accurate patient results in a timely fashion even in the presence of interfering substances; however, these are currently confined to reference methods.