Troponin elevation can, among others, be due to myocardial infarction, acute inflammation or structural heart disease. Formation of macrocomplexes against troponin is an underestimated cause for persistent troponin elevation. Polyethlylene glycol precipitation (PEG) can differentiate macrotroponin from real troponin elevation, but cut-off values for PEG have not been established. PEG is analyzed in patients with acute coronary syndrome undergoing invasive coronary angiography and compared to healthy marathon runners who have undergone cardiological pre-participation screening and have rested for 24 hours.