None apparentNo convincing alternative cause

Chronic thrombocytopeniaLow platelets predate current exposure

New thrombocytopenic drugNew non-heparin medication known to lower platelets

Severe infection / sepsisAlternative consumptive/inflammatory cause

Severe DICDisseminated intravascular coagulation

Intra-arterial devicee.g. IABP or other arterial mechanical support

Recent CPBCardiopulmonary bypass within 96 hours

Other causeAnother clinically convincing explanation