VARIABLES INFLUENCING THE THROMBOSTAT-4000 - RECOMMENDED STANDARDIZATION

The in vitro bleeding test (IVBT) (Thrombostat 4000) was performed on blood samples from healthy blood donors using a ''preliminary standard test.'' Only one factor of the test procedure was changed each time. We found the following parameters to have a significant influence on t he test results: time interval between sampling and testing, diameter of the filter's aperture, capillary diameter, aggregating agents and t heir concentration, temperature of the blood and cartridges, method of drying the capillaries, the aspiration pressure, and the hematocrit o f the blood sample. According to our data, we propose a standard IVBT for routine application and modifications for special diagnostic use.