In vitro heparinization showed that ACT and log APTT correlated linearly with blood heparin levels and WBCT, with 2-2.5 times baseline WBCT corresponding to an APTT of 2.7-4.2 times baseline.
How do APTT, WBCT, and ACT correlate with each other and with blood heparin levels in vitro?
APTT and ACT can be used to monitor heparin effect, but the nonlinear relationship between APTT and WBCT must be considered if substituting one for the other.
In vitro heparinization experiments were done to determine the heparin sensitivity and statistical correlation of the three coagulation tests in order to see whether automated whole blood coagulation time (ACT) and activated partial thromboplastin time (APTT) could be substituted for whole blood coagulation time (WBCT). WBCT and ACT were linearly related to each other and to blood heparin level. Log APTT gave a linear correlation with blood heparin level and with the two whole blood coagulation tests. Two to 2½ times baseline WBCT corresponded to an APTT of 2.7 to 4.2 times baseline (average 90 to 150 sec), and to an ACT of 1.6 to 2.2 times baseline (average 410 to 570 sec). All three tests were sensitive enough to heparin effect for use in monitoring of patients. Any attempt to substitute APTT for WBCT must take into consideration the nonlinear relationship between APTT and WBCT.
Schriever et al. (Sat,) reported a other. In vitro heparinization was evaluated on Heparin sensitivity and statistical correlation of ACT, APTT, and WBCT. In vitro heparinization showed that ACT and log APTT correlated linearly with blood heparin levels and WBCT, with 2-2.5 times baseline WBCT corresponding to an APTT of 2.7-4.2 times baseline.