Evaluation of the Activated Whole Blood Clotting Time (ACT) in Vitro

Abstract

The activated whole blood clotting time ( A m was analyzed in vitro using blood samples from normal individuals and from patients with heart disease, scheduled for open heart surgery. The ACT was found to be normally distributed in a group of normal individuals with a mean d 135 sec. In patients with heart diseases, the average ACT was slightly shorter than in normal individuals. A linear relationship between ACT and heparin concentrations was established. Haemdilution and depletion of platelets did not significantly influence the ACT. When a clean venipuncture with disposable needles is used, ACT is a reliable, uncomplicated bedside technique by which heparinisation can be monitored.

Monitoring Heparin and Protamine Therapy during Cardiopulmonary Bypass by Activated Clotting time

“…The activated whole blood clotting time has been studied in vitro. 6 In healthy controls, the ACT is normally distributed with a mean of 131 seconds (SD 6).…”