The platelet count accuracy of platelet concentrates obtained by using automated analysis is influenced by instrument bias and activated platelet components

Background and Objectives The blood platelet content (in numbers) of platelet concentrates is required for production quality control and to predict clinical responses. Materials and Methods This study compared the performance of automated counting from impedance and optical instruments to data from immunoplatelet reference analysis. Results All methods showed good linearity with evidence of significant instrument-specific deviations from the line of agreement. Relational formulae largely corrected bias, but did not resolve platelet count variability. A second confounding factor, related to the proportion of small (activated) platelets, was also shown to contribute to intermethod discrepancies. Conclusions Blood processing centres should establish correction factors for each instrument compared to reference methods, such as the immunoplatelet count.