PLATELET FUNCTION DISORDERS - Platelet function can be affected by a number of different disease processes including polycythemia vera, leukemia, myelofibrosis, renal failure, multiple myeloma, and some medications (e.g. penicillins, salicylates, phenothiazines). Disturbed blood clotting can be manifested by: easy bruising, bleeding gums, nosebleeds, abnormal vaginal bleeding, rectal bleeding, skin rash, vomiting blood, coughing up blood, or blood in the urine. A measure of bleeding time and coagulation profile will be part of the evaluation.