Hematologic parameters are commonly utilized in sports medicine and antidoping testing. However, there are no universally accepted methodologies for comparing the performance of automated blood analyzer systems. To address this problem, we selected and examined 19 studies from a review of literature published from 2000 to 2010. Meaningful discrepancies were found between measurements obtained with different analytical systems. Because harmonization and clear standardization of methods are lacking, the analytical variability often largely exceeds intra- and inter-individual biological differences, producing equivocal test results unreliable for clinical and antidoping testing. A central criticality to applying the Bayesian approach is analytical variability, but the use of different analytical technologies precludes the comparison of inter-methods for determining the robustness of blood variables and their clinical significance. Therefore, future multicenter studies are needed to compare analytical methodologies and blood analyzer systems, and to establish worldwide-accepted standards and quality control protocols.