The management of thrombocytosis

Since the work of James Homer Wright more than 80 years ago (l), it has been universally accepted that blood platelets are produced by the megakaryocytes and constitute anucleate fragments of the cytoplasm of these giant cells. Non-activated platelets circulate as discoidal cells 2-3 pm in diameter, and most clinicians would agree that the normal human peripheral platelet count should range from 150-350 x 109/l. It is proposed that a thrombocytopenic state is present if the platelet count is below 100 x 109/l. Conversely, the term thrombocytosis implies that the peripheral platelet count is greater than 400 x 109/l.