<qa>  What is the thrombocytopenia less than 50,000 microliters?Gastrointestinal or internal bleeding except microscopic hematuria within the previous two weeks; active peptic ulcer disease; familial or acquired bleeding diathesis not attributable to heparin administration prothrombin time greater than 14 s, APTT greater than 35s, fibrinogen less than 150mgdl; thrombocytopenia less than 50,000 microliters. 