Malicev E, et al. - This study involved the estimation of the level of heparin-induced antibodies and the flow cytometric functional assay in patients with heparin-induced thrombocytopaenia (HIT). Higher ELISA optical density (OD) values raised the possibility of the presence of platelet-activating anti-heparin/platelet factor 4 (PF4) antibodies. Yet, there was no requirement for the improvement of ELISA cut-off value for positive result.