Novel approaches to quality control and external quality assessment for platelet function testing with a focus on the platelet function analyser (PFA-100 and PFA-200)

Platelet function testing is a key diagnostic activity within hematology laboratories associated with advanced hemostasis diagnostics. Platelets represent a key component of primary hemostasis, and deficiency and/or defects, either congenital or acquired, leads to bleeding diathesis in affected individuals. There are various levels of platelet function tests, from simple screens, to complex functional assays, as well as molecular analysis. Platelet function testing has evolved to now incorporate a variety of processes, such as whole blood aggregometry, light transmission aggregometry (LTA), testing by platelet function analyser (PFA) -100 (or -200), flow cytometry, and many other methodologies. Despite some of these tests being available now for decades, and/or continuously evolving, internal quality control (IQC) and external quality assessment (EQA) is limited and made difficult by the nature of the tests and test material, the latter typically representing functional cellular material (i.e., platelets). The current review looks at platelet function testing from the perspective of diagnostic screening, and highlights current limitations, as well as potential solutions that will enable more effective and accurate testing in the future. The primary focus of the review, however, is on IQC and EQA for the platelet function analyser (PFA-100 and PFA-200).