Changes in Platelet Volume in Various Patients with Thrombocytopenia and Thrombocytosis as Observed by the Platelet Saponin Test
Platelet volume, the expansion ratio (ER) and the shrinkage ratio (SR) were measured by the platelet saponin test in various patients with thrombocytopenia and thrombocytosis. In patients with platelet counts of less than 10×10 4/μl the platelet volume increased to above the normal range (p<0.001, t-test) with reduction of the ER (p<0.001, t-test). The SR was heightened in thrombocytopenias due to diminished megakaryopoiesis resulting from enhanced platelet aggregation. On the other hand, in thrombocytopenias due to increased platelet destruction the SR level was normal notwithstanding and enlarged platelet volume presumably due to lowered platelet activity. In thrombocytosis with platelet count above 40×10 4/μl, both the platelet volume (p<0.05) and the ER (p<0.01, t-test) were smaller than in normal subjects. The numerical results obtained by the platelet saponin test reflect the qualitative platelet abnormalities in patients with thrombocytopenia and thrombocytosis.