Prospective evaluation of automatized PF4/heparin immunoassays HemosIL HIT-ab (PF4-H) for the diagnosis of heparin-induced thrombocytopenia.

[heparin-induced thrombocytopenia]

Recently , rapid immunoassays have been developed to allow the detection of antibodies anti-PF 4 /heparin . In this prospective study , we evaluated the performances of a automatized immunoassay (HemosIL HIT -Ab ) in comparison with an ELISA (Zymutest HIA IgG ) used for the diagnosis of heparin-induced thrombocytopenia (HIT ) in association with the 4 T 's score .According to the 4 T 's score , samples with score ≤3 had no further analysis . Two immunological assays Zymutest HIA IgG and HemosIL HIT -Ab were performed in samples with score ≥4 . In patients with at least one positive immunological assay or two negative immunological assays but with high -pretest probability (4 T 's score ≥6 ), HIT was screened by one functional assay using washed platelets .The sensitivities of both assays were excellent and comparable (100 %). The specificity was 92 .3 % for ELISA and 91 .2 % for HemosIL HIT -Ab . The analysis of the operating characteristics showed that both assays have almost identical ROCs (AUROC , 0 .9951 and 0 .9853 , respectively , for ELISA and HemosIL HIT -Ab ) and the calculating of the κ coefficient revealed a good agreement (0 .67 ).Performance characteristics of the HemosIL HIT -Ab are comparable to the Zymutest HIA IgG . The HemosIL HIT -Ab can be used in association with the 4 T 's score to rule out HIT .