The search for a myocardial ischemia marker. The case of albumin modified by ischemia

The search for a suitable and reliable marker of myocardial ischemia has led to the proposal of employing the cobalt binding capacity of total serum assuming that ischemic modifications of circulating albumin would markedly decrease its ability to bind cobalt. This test (IMA, Ischemia-Modified Albumin) can be easily implemented on most of the technological platforms employed for clinical chemistry assays. It is simple and rapid and suitable for most of the diagnostic purposes of emergency medicine. This assay has been successfully employed to detect myocardial ischemia in various clinical studies and, despite a low specificity for myocardial ischemia, its high sensitivity and negative predictive value have pointed out its possible role as a first-line assay in clinical setting of patients with chest pain admitted to the Emergency Department. The low specificity toward ischemic events occurring to myocardium is challenging its use in clinical conditions associated with tissue ischemia or whole body hypoxia. Few caveat, however, must be taken into account. They include the clear identification of the proteins responsible for cobalt binding, the normalization of the results for the serum concentration of the binding sites, the standardizations of the assays employed. Large randomized trials are also absolutely needed to undoubtedly identify the potential and the limit of this new and promising biomarker.