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

Abstract

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. ? 2005 Elsevier B.V. All rights reserved.