Relationship of mean platelet volume to platelet count in morphologic evaluation of thrombopoiesis.

A graph of the relationship between mean platelet volume (MPV) and platelet count (TPK) was constructed out of 158 haematologically normal individuals, 19 patients with thrombocytopenia and 63 patients with thrombocytosis. Patients with thrombocytopenia and thrombocytosis whose bone marrows were found to show adequate or increased, morphologically normal, thrombopoiesis were included in the graph. The graph was found to exhibit the previously known inverse relationship between TPK and MPV extended into thrombocytopenic values and is thought to represent an intact marrow function capable of meeting the increased demands of thrombopoiesis. On the other hand, 15 patients whose bone marrows were showing evidence of hypoplastic thrombopoiesis fell outside the region representing intact marrow function. The position of an individual's values of MPV vs TPK in a coordinate system with these variables on the axes correlates well with the morphologic evaluation of thrombopoietic function and seems to be clinically useful.