Type 2 HIT is an antibody-mediated, prothrombotic drug reaction first described in 1973, characterized by thrombocytopenia occurring about one week after heparin initiation, frequent thrombotic events, and the presence of heparin-dependent, platelet-activating anti-PF4 antibodies (1, 2, 21, 22). Here, PF4 is linked to Thrombocytopenia.