['To examine the diagnostic performance of glycogen-phosphorylase-isoenzyme-BB (GPBB) combined with cardiac troponin I (cTnI) in acute coronary syndrome (ACS).', 'Sixty patients with chest pain were investigated; GPBB and cTnI were measured.', 'ACS was confirmed in 31 patients; cTnI was >0.07 μg/L in 15 patients and GPBB was >10 μg/L in 6 patients. Areas under ROC curves were similar: 0.854 (cTnI+GPBB) vs. 0.843 (cTnI), p=0.728.'] Is performance of glycogen phosphorylase isoenzyme BB weak in the detection of patients with non-ST-elevation acute coronary syndrome?