Ischemia-Modified Albumin (IMA) is a marker of myocardial ischemia rather than myocardial injury. Early clinical manifestations of myocardial ischemia are often vague and diverse, may include chest pain, upper abdominal and arm discomfort, panting, malignant and vomiting, so it is not easy to identify. Studies have found that IMA increase in 5 ~ 10 min after ischemia occurred and last about 3~6 h before recovered to normal level. This is crucial for the early detection of acute myocardial ischemia and recurrent myocardial ischemia within 24h. Myocardial ischemia is the most common cause of acute coronary syndrome, IMA determination can used for accurate risk stratification and prognosis judgement of acute coronary syndrome. 

In the test, normal albumin exists as active form in serum or plasma, N-terminal of albumin combine with Co+ while adding cobalt chloride solution, then concentration of free Co+ in the solution decrease. The serum or plasma of patients with myocardial ischemia contains more IMA, the ability of albumin binding to Co+ decreased while adding the same amount of cobalt chloride solution, so free Co+ concentration higher. The higher concentration of free Co+ formed more colored products when adding dithiothreitol (DTT). Colorimetric test at a specific wavelength, the absorbance is proportional to the concentration of free Co+. The IMA concentration in the sample can be calculated by comparing the calibrator result with same processing.