Platelet survival, platelet factor-4 and bleeding time in myeloproliferative disorders.

In 27 patients with myeloproliferative disorders observations on thrombohaemorrhagic complications, platelet function tests and spleen size were made. Sixteen patients had thrombotic or haemorrhagic episodes. All 27 patients had elevated platelet factor-4 and 25 patients had a shortened platelet survival. Patients with myelofibrosis had a significantly shorter platelet survival than patients with polycythaemia vera (p less than 0.05). Seven out of 23 patients investigated had prolonged bleeding time. The observed abnormalities of platelet function tests were not related to thrombohaemorrhagic complications or spleen size.