Background: In this study, our purpose was to evaluate the analytical performances of the STA R Max and CN-3000, and compare the results of both for PT, aPTT, fibrinogen, D-dimer, and factor VIII, and also to show the influence of hemolysis on PT, aPTT, and fibrinogen assays.
Methods: Three hundred ninety-five randomly-selected blood samples from residual material from Istanbul Faculty of Medicine, Central Laboratory workflow comprised the study group. PT, aPTT, fibrinogen, D-dimer, and factor VIII activity were done using both analyzers. Analytical performances were determined through precision, linearity, and comparability studies. Artificial hemolysis was performed through freezing-thawing and mechanical-sheer methods.
Results: Intra-assay and between-day CVs% of PT and aPTT were lower than 5% for STA R Max and CN-3000. Only the within-run and between-day CVs% of fibrinogen and the between-day CVs% of D-dimer were higher than 5%, but in acceptable targets. Intra-assay and between-day CVs% of FVIII on the CN-3000 were 3.5% and 12.3% at the low and 2.5% and 5.3% at high level, and 1.8% and 3.7% at the low and 6.3% and 5.9% at high level on the STA R Max. The comparison results of PT, aPTT, fibrinogen, and D-dimer were good (r > 0.91), also good correlations were obtained for FVIII activity > 40 IU/dL and FVIII between 5 - 40 IU/dL (r = 0.89). The results of the hemolysis study were within acceptable limits of the recommended criteria of Fraser and the manufacturer.
Conclusions: CN-3000 and STA R Max coagulation analyzers are accurate and highly precise systems for safe use in clinical diagnostic applications. The interferences obtained for both analyzers were found to be within accepted targets.