Comparing a piezoelectric quartz crystal with an optical coagulometer in monitoring high-dose heparin therapy by determining whole blood activated partial thromboplastin time and activated clotting time

The activated partial thromboplastin time (aPTT) and the activated clotting time (ACT) were examined ex-vivo and in vitro, respectively, using a coagulometer based on a piezoelectric quartz crystal (PQC) sensor. A magno-mechanical and an optical coagulometer were employed to determine ACT and aPTT values in high-dose heparin therapy to evaluate the performance of the coagulometers. The correlations between aPTTs with a PQC coagulometer and ACTs with a magno-mechanical coagulometer were sufficient (>0.91) for a high-dose range (0-4 units/ml) of heparin in blood plasma and whole blood. Ex-vivo investigations of high-dose heparin therapy were also conducted to evaluate the analytical performance (sensitivity and specificity) of a PQC coagulometer, based on the receiver-operating characteristic. No false-positive or false-negative result was obtained in distinguishing the coagulation effect of 10,000 units of heparin administrated to subjects, using a suitable cut-off value (101 s) for whole blood aPTTs (WBaPTT) measured using a PQC coagulometer. The WBaPTT outperformed PLaPTT with a PQC coagulometer in terms of both safety (sensitivity = 100%) and accuracy (specificity = 97) (sensitivity = 100%, specificity = 87% in PLaPTT) and OCaPTT (sensitivity = 100%, specificity = 87%) with an optical coagulometer.