Analytical performance comparison of Roche Cobas t 711 and Sysmex CS-2500 with assessment of interference effects

Abstract Objectives Coagulation tests are essential for diagnosing bleeding disorders and for monitoring anticoagulant therapy. However, analyzer-dependent variability and pre-analytical interferences such as hemolysis and lipemia may affect test accuracy. This study aimed to compare the analytical performance of Roche Cobas t 711 and Sysmex CS-2500 analyzers for Prothrombin Time (PT), International Normalized Ratio (INR), Activated Partial Thromboplastin Time (APTT), and fibrinogen measurements, and to evaluate the effect of hemolysis and lipemia on test results. Methods Plasma samples from 100 patients were used. Repeatability and intermediate precision were assessed, and method comparison was performed using Passing-Bablok regression and Bland-Altman analysis according to Clinical and Laboratory Standards Institute (CLSI) EP09-A3 guideline. Artificial hemolysis and lipemia were induced to simulate pre-analytical interference. Results Both analyzers showed acceptable precision (coefficient of variation [CV] <5 %). Fibrinogen measurements showed strong agreement (median difference −2.17 %), while PT and APTT results differed significantly (PT: −25.21 %; APTT: 22.76 %). PT was more affected by hemolysis (>6 g/L) and lipemia (>11.3 mmol/L) than APTT. These interferences appeared to affect Roche Cobas t 711 to a greater degree because of its optical detection method. Conclusions Although both devices performed reliably under standard conditions, significant differences were observed in PT and APTT measurements. Hemolysis and lipemia also caused clinically relevant bias at certain levels, especially in PT. Local validation and awareness of interference effects are essential for accurate coagulation testing, highlighting the need for careful testing of multiple measurands when transitioning between systems.