DEVELOPMENT AND PRACTICAL USE OF THE NEW QUANTITATIVE BLEEDING-TIME TEST APPARATUS

We have developed a new computerized system for measurement of quantit ative bleeding time (QBT) to detect subtle abnormalities of primary he mostasis that are difficult to detect with the standard bleeding time determination. This new apparatus can simultaneously measure the bleed ing time (BT; sec), amount of total blood loss (Tv; mu l), maximum ble eding rate (Rmax; mu l/sec) and bleeding pattern from the bleeding tim e incision. We have also developed a new holder for the Simplate that enables more consistent incisions and thus improves the reproducibilit y of the BT test. In this study, the newly developed QBT test was perf ormed in 137 normal healthy volunteers and 10 patients having defined abnormalities of either primary or secondary hemostasis. Comparisons o f the standard BT test and our QBT were made in 5 normal subjects and 7 thrombocytopenic patients. Additionally, 6 normal subjects were exam ined with both tests before and after administration of aspirin. Those results show that our QBT appears to be a more sensitive indicator of primary hemostasis than the standard BT method.