HEMATOLOGICAL PARAMETERS INFLUENCING THE THROMBOSTAT-4000

The effects of platelet counts, hematocrit, and leukocyte counts were studied on the closure times of the Thrombostat 4000 (in-vitro bleedin g time, IVBT). Closure times became longer with platelet counts <50 x 10(9)/L; an inverse linear correlation could be established. Hematocri t was also inversely correlated with the closure time. At constant pla telet counts a hematocrit of 55% yielded an immediate closure of the f ilter, while with a hematocrit <15% no closure times could be measured . At constant platelet counts and hematocrits, nomonuclear and polymor -phonuclear leukocytes also influenced closure times; increased counts resulted in shorter closure times. Leukocytes from a patient with chr onic myelocytic leukemia had the same effects.