Verification of assays,whose responsibility is it?

Koerbin et al., ¹ have stated that ‘international guidelines have recommended that the 99th percentile and the 10% CV need to be validated for each troponin assay by routine testing laboratories’. ² While this may not reflect their opinion, they have missed an opportunity to state what their position on this contentious statement is.

My opinion is that the extensive validation they have carried out is the task of a government-funded reference laboratory, not of individual routine laboratories. Our role is to establish within- and between-day variation for analytes, on our analysers in our laboratories. We can also take one or two samples at the high end of the analytical range and serially dilute them to confirm linearity and limit of detection of the assay. When we change from one assay to an alternative assay for the same analyte, we also must establish the relationship between them. Beyond this, we do not have the resources to carry out precision profiles or establish reference ranges.

It is also important that manufacturers fulfil their obligation by giving an indication of reference ranges outside of the Western world, for example among Asian populations where they sell huge numbers of their kits.

In our laboratory we could attempt to establish reference values for troponin, for example, among our presumed healthy laboratory and medical staff, but we do not have the resources to do stress echocardiography or other clinical tests to establish cardiovascular health. We thus run the risk of producing skewed data as the authors ¹ describe in their study, where three healthy subjects had to be excluded. Finally, the outcome of their thorough and detailed study ¹ was to verify the 99th percentile and limit of detection concentrations already established by the manufacturer. Similar findings have been reported by two other groups ^3,4 using a total of 1162 subjects.

I am not being critical of this particular study, but feel that clarification on whose responsibility it is to undertake proper and rigorous assay validation is required.

DECLARATIONS

Competing interests: None.

Funding: None.

Ethical approval: Not applicable.

Guarantor: JJF.