Acute stent thrombosis remains one of the most important concerns in clinical cardiology. The mechanism is not fully understood but a prothrombotic state is a key component. We describe a case of acute stent thrombosis, within an hour of rescue angioplasty, despite use of full dose fibrinolytic (reteplase) and antiplatelet therapy (aspirin and clopidogrel). Risk of acute stent thrombosis was predicted an hour earlier, when the patient was clinically well, by a novel near-patient test of thrombotic and thrombolytic status (in vitro). Subsequent stent thrombosis was visualised angiographically (in vivo) and confirmed by extraction of the thrombus (ex vivo). The near-patient test sensitively detected reversal of the prothrombotic state after abciximab treatment. We believe this is the first description of the clinical use of a near-patient test within the cardiac catheterisation laboratory to predict risk of imminent stent thrombosis.