Circulating Megakaryocytes in Blood from the Antecubital Vein in Healthy, Adult Humans

A total of 21 healthy, adult men and 30 healthy, adult women aged 21–73 years were investigated for circulating megakaryocytes in the antecubital vein using the saponin-haemolysis leucoconcentration technique. In the males, the number of megakaryocytes in 1.5 ml blood varied from 1 to 20, the arithmetic mean being 10 megakaryocytes. In the females, the number varied from 0 to 29 megakaryocytes and the arithmetic mean was 7.6 megakaryocytes. No significant difference was found between the values for the two sexes. There was no correlation between the number of megakaryocytes and platelets or leucocytes. 99 % of the observed megakaryocytes were naked nuclei or had sparse cytoplasm and 1 % had copious cytoplasm. Megakaryocytes without copious cytoplasm may be regarded as normally occurring cells in the peripheral venous blood.