Evaluation of the Analytical Properties of the Diagon CoagXL Coagulation Analyzer

This study aims to evaluate the analytical properties of the DIAGON CoagXL (Budapest, Hungary) coagulation system.

The study includes a total of 212 normal, 49 pathologic plasma samples sent to our laboratory. The par-tial thromboplastin time (PTT) and activated partial thromboplastin time (aPTT) measurements were performed on the Diagon CoagXL and Stago StaR coagulometers. The precision, method comparison, carry-over, activity determination, and reference range verification studies were performed with Diagon CoagXL, the test analyzer.

In the precision study performed with normal and pathologic plasma samples for the PT and aPTT tests, the within-day coefficient of variation (CV%) was 1.9 in the normal and 0.68 in the pathologic plasma for the PT, and for the aPTT it was 0.61 in the normal and 0.9 in the pathologic plasma. The between-day CV% was 1.6 in the normal plasma and 5.5 in the pathologic plasma for the PT and 3.7 in the normal plasma and 2.1 in the pathologic plasma for the aPTT. In the comparison study, the entire group mean ± standard deviation (mean ± SD) value for the INR was found to be 3.13 ± 1.26 in the CoagXL and 2.67 ± 0.82 in the StaR analyzer. The difference between these values was statistically significant (p < 0.006). For aPTT, mean ± SD value was found to be 39.44 ± 25.02 seconds (sec) in the CoagXL analyzer and 43.4 ± 27.63 sec in the StaR analyzer. The difference between these values was not statistically significant (p > 0.5). In the carryover study, the carryover value was -0.16 for the PT and 0 for the aPTT, which was under the allowable limit value (< 3 SD). In the percent activity determination study, regression equation of prothrombin activity (%) versus time (sec) was found as y = 341.6567 ± 37.1920x + 1.0913x2 (R2 = 0.97). The reference range verification analyses reveal that the manufacturer ranges were acceptable.

Verification studies of CoagXL analyzer system was acceptable. But in comparison studies of PT we saw that there are still problems with recommended INR system.