Heparin is integral to the treatment of acute coronary syndromes, deep vein thrombosis and its prophylaxis. An undesirable result of recurrent heparin use is rapid onset heparin-induced thrombocytopenia (HIT) within hours of exposure. This catastrophic condition is frequently diagnosed too late for therapy to be effective. We describe a case of fatal rapid onset HIT, analyze current evidence to diagnose this condition and propose a way so that it can be prevented.