Analytical performance evaluation of Sysmex CS-2500 and Stago STA Compact

: The Sysmex Coagulation System-2500 (CS-2500) is a fully automated coagulation analyzer that uses the optical reaction method. In this study, we aimed to evaluate performance characteristics of the CS-2500 in two coagulation tests [prothrombin time (PT) and activated partial thromboplastin time (aPTT)] at our hospital laboratory. PT and aPTT measurements were performed using the CS-2500 and STA-Compact Diagnostica Stago coagulometers (STA-Compact). Then, precision, accuracy, reference range verification, and method comparison statistics were performed. In the precision study, which was performed with normal and pathologic controls for the PT-international normalized ratio (INR) and aPTT tests, all coefficient of variation% were found less than 3.5%. In the comparison study, the Passing-Bablok regression analysis demonstrated the good agreement between each analyzer for PT-INR (y = -0.081 + 1.07x and r = 0.962) and for aPTT (y = 5.498 + 0.86x and r = 0.944). Both analyzers exhibited less than 9.9% bias in the accuracy study. The reference range verification analyses revealed that the manufacturer ranges were acceptable. The verification studies of the CS-2500 coagulation system were acceptable; however, in the comparison studies, there were small differences between STA-Compact. Overall, we propose that these differences could be eliminated in future standardization studies performed to use the same reference ranges for all systems.