THE VOLUME OF BLOOD SHED DURING THE BLEEDING-TIME CORRELATES WITH THEPERIPHERAL VENOUS HEMATOCRIT

The relation among the bleeding time, the peripheral venous hematocrit , and the amount of blood shed at the template bleeding time site has not been previously defined. We studied this relation in 227 persons: 26 were patients with idiopathic thrombocytopenic purpura (ITP), 137 w ere patients with a variety of other bleeding disorders, and 64 were h ealthy subjects. The bleeding time (mean +/- SD) for the healthy group was 7.1 +/- 1.2 minutes, and the amount of shed blood was 136.4 +/- 4 7.2 mu L; in patients with ITP, the bleeding time was 14.0 +/- 4.1 min utes and the shed blood was 508.1 +/- 387 mu L; and in the group with other bleeding disorders, the mean bleeding time was 9.0 +/- 3.5 minut es, and the amount of shed blood was 224.7 +/- 184 mu L. Bleeding time s for all persons studied showed a significant correlation of 0.75 for the amount of shed blood on the filter gaper and a significant correl ation of 0.28 for the peripheral venous hematocrit. There was also a s ignificant correlation between the bleeding time and the platelet coun t in patients with ITP. This study demonstrates that the volume of blo od shed at the bleeding time site correlates with the peripheral venou s hematocrit and emphasizes the contribution of the hematocrit to prim ary hemostasis in healthy subjects and patients with bleeding disorder s.