Heparin-Induced Thrombocytopenia is a reaction associated with a reduced platelet count secondary to the use of the anticoagulant heparin. It occurs due to a non-immune reaction or antibodies that activate platelets and their premature removal from circulation. This is assessed by an enzyme-linked immunoassay to detect HIT-associated antibodies. Management involves heparin stoppage, platelet monitoring, and complication prevention.