Insignificant role of the N-terminal cobalt-binding site of albumin in the assessment of acute coronary syndrome: discrepancy between the albumin cobalt-binding assay and N-terminal-targeted immunoassay.

The aim of this study was to evaluate whether the N-terminus of human serum albumin (HSA) has a role in the cobalt binding detected using albumin cobalt-binding (ACB) assay. We compared the results obtained using an enzyme-linked immunosorbent assay (ELISA) for N-terminal-modified HSA with those of a conventional ACB assay in two groups: acute coronary syndrome (n = 43) and non-ischemic chest pain (n = 39). ACB and cardiac troponin-I levels were higher in the acute coronary syndrome group. No significant correlation between ACB assay and ELISA results was observed in either of the two patient groups. In acute chest pain patients, the N-terminal site of HSA has a negligible or limited role in cobalt binding in the ACB assay.