INCIDENCE AND DIAGNOSIS OF EDTA-DEPENDENT PSEUDOTHROMBOCYTOPENIA IN ACONSECUTIVE OUTPATIENT POPULATION REFERRED FOR ISOLATED THROMBOCYTOPENIA

Among 111 patients referred to our outpatient clinic for isolated thro mbocytopenia during a 24-month period, 17 (15.3%) cases of EDTA-depend ent pseudothrombocytopenia (EDTA-PTCP) were identified. EDTA-PTCP repr esented the second most frequent cause of thrombocytopenia in this pop ulation. The diagnosis was confirmed by the following findings: (a) no rmal platelet numbers immediately after blood withdrawal; (b) progress ive fall of platelet counts and evident platelet clumping over time, o nly in EDTA-anticoagulated blood. A simple, inexpensive and quick diag nostic method was devised, that consists in evaluating the platelet nu mber in a blood sample anticoagulated with EDTA immediately after bloo d withdrawal and 4 h later.