Abstract: Objective: To estimate the value of ischemia modified albumin(IMA) in early diagnosis of acute coronary syndrome(ACS).Methods: The venous blood samples from 56 patients with ACS(ACS group),30 patients with non-ischemia chest pain(NICP group) within 3 h of onset and 155 healthy controls were assayed,and the IMA,MB type creatine kinase(CK-MB) and cardiac troponin(cTnI) levels were compared among the three groups.The value of the myocardial markers in early diagnosis of ACS was estimated by the ROC curve.Results: The IMA of the 3 groups were(0.500±0.017),(0.400±0.082) and(0.326±0.024) absorbance unit,respectively;the serum level of IMA in ACS group was higher than that in healthy controls and NICP group(P<0.01).The area under curve of IMA was larger than that of cTnI and CK-MB;the sensitivity of IMA was higher than that of CK-MB and cTnI;the specificity of IMA was more obvious than that of cTnI>CK-MB.The best cutoff value of IMA,CK-MB and cTnI was definite.Compared with the NICP group,the positive likelihood ratio and negative likelihood ratio of IMA for ACS were 10.7 and 0.008,respectively;compared with the healthy controls,the positive likelihood ratio and negative likelihood ratio of IMA for ACS were 8.23 and 0.013,respectively.Conclusions: IMA is superior to cTnI and CK-MB in diagnostic of ACS at the early stage.