Diagnostic value of ischemia-modified albumin in patients with suspected acute coronary syndrome.

INTRODUCTION: Ischemia-modified albumin (IMA) has been proposed as a useful rule-out marker for the diagnosis of acute coronary syndrome (ACS) in the emergency department. This study evaluated the ability of IMA to predict the acute myocardial infarction (AMI) diagnosis in a population of chest pain patients.

METHODS: The study population comprised 107 subjects (men, 62%; women, 38%) admitted with suspected ACS. None of the patients had ST-segment elevations that qualified for immediate revascularization. Ischemia-modified albumin was determined from serum with albumin cobalt binding test (Inverness Medical Innovations Inc, Stirling, UK). Furthermore, cardiac troponin T, creatinine kinase MB mass, myoglobin, and heart-type fatty acid binding protein (H-FABP) were determined on arrival, after 6 to 9 hours, and after 12 to 24 hours. All patients had at least 2 blood samples taken to exclude/verify the AMI. AMI was defined by a cardiac troponin T level greater than 0.03 microg/L.

RESULTS: Thirty-three percent of the patients (n = 35) had a final diagnosis of AMI. The sensitivity of admission IMA for a final diagnosis of ACS was 0.86 (95% confidence interval [95% CI], 0.69-0.95). Specificity was 0.49 (95% CI, 0.36-0.60). Negative predictive value was 0.88 (95% CI, 0.72-0.95). The optimal cutoff threshold derived from the receiver operating characteristics (ROC) curve (ROC analysis) was determined as 91 U/mL. The area under the ROC curve was 0.73. Ischemia-modified albumin did not, at any time, provide superior sensitivity or specificity compared with other biomarkers. We do not find the data supportive of IMA as a standard marker in the emergency department.