Incidence of anti-heparin/platelet factor 4 antibodies and heparin-induced thrombocytopenia in medical patients

Objective: Heparin-induced thrombocytopenia (HIT) is a life threatening complication of heparin therapy, causing thrombosis. The aim of our study was to find out the frequencies of HIT antibody seroconversion and clinical HIT in Turkish medical patients on different forms of heparins. Materials and Methods: Our study included 61 patients who were an unfractionated heparin (UFH) (n: 37) and low molecular weight heparin (LMWH) (n: 24) therapies. The frequency of HIT antibody formation was determined by means of antigenic (ELISA), and functional assays (serotonin release assay-SRA). Results: The seroconversion rates in UFH and LMWH groups were found to be 18.9% and 4.1% (ELISA), and 8.1% and 4.1% (SRA), respectively. One patient (2.1%) on UFH therapy developed deep vein thrombosis. No thromboembolic event was observed in patients taking LMWH. Conclusion: Seroconversion rates by means of antigenic and functional assays and clinical HIT were more common in patients on UFH than patients on LMWH therapy. (Turk J Hematol 2009; 26: 171-5)