Abstract: Objective To estimate the reliability of heart-type fatty acid-binding protein(H-FABP) for identifying acute coronary syndrome(ACS) in the early stage of chest pain onset.Methods This investigation was conducted based on a small population consisting of 40 healthy individuals,19 established AMI patients and 20 unstable angina pectoris(UAP) patients.Serum H-FABP concentrations were measured in these subjects by sandwich ELISA,and receiver operating characteristics(ROC) curves for H-FABP for diagnosing AMI and UAP against normal subjects were then generated respectively.The areas under curve(AUCs) were calculated,and 0.5 was defined as the critical value of AUC to evaluate the diagnostic ability.Results The concentrations of H-FABP in healthy individuals,AMI patients and UAP patients were 1.29±0.64,24.45±32.40 and 1.95±3.11 ng/ml,respectively;AUCAMI and AUCUAP were 0.978(95 %CI :0.948-1.000) and 0.503(95 %CI :0.334-0.671) respectively,and the former was significantly greater than 0.5.Conclusions In the early stage of chest pain onset H-FABP detection is sufficient in distinguishing AMI patients from healthy individuals,but not capable of distinguishing UAP patients from healthy individuals.H-FABP may be used as a diagnostic biochemical marker in the early stage of AMI