Incidence of antiheparin-platelet factor 4 antibodies and heparin-induced thrombocytopenia in Turkish patients undergoing cardiac surgery.

The frequency of antiheparin-platelet factor 4 antibodies by means of antigenic and functional assays ((14) C-serotonin release assay and citrated plasma platelet aggregation) was determined in 115 Turkish patients undergoing cardiac surgery. Blood samples were taken immediately before surgery and on days 5 and 10 +/- 2. Platelet counts were recorded and thrombotic events were determined by clinical methods. Antibody generation measured by enzyme-linked immunosorbent assay before surgery (n = 44) and on days 5 (n = 44) and 10 (n = 115) was 15.9%, 34.1%, and 65.2%, respectively. Positive samples from functional assays were 4.4% on day 0 and 7.0% on day 10. All positive samples had been negative on day 0. A high frequency of antiheparin-platelet factor 4 antibody generation and a low frequency of clinical heparin-induced thrombocytopenia were determined in these patients. These results obtained for Turkish patients are similar to those of other studies of heparin-induced thrombocytopenia.