A novel assay for cobalt-albumin binding and its potential as a marker for myocardial ischemia—a preliminary report

• Published in: The Journal of emergency medicine 2000-11, Vol.19 (4), p.311-315
• Main Authors: Bar–Or, David, Lau, Edward, Winkler, James V
• Format: Article
• Language: English
• Subjects: Aged; Binding Sites; Biological and medical sciences; Biomarkers - blood; Cardiology. Vascular system; Case-Control Studies; chest pain; Chest Pain - blood; Chest Pain - diagnosis; Chest Pain - etiology; cobalt; Cobalt - metabolism; Colorimetry - methods; Coronary heart disease; Decision Trees; diagnostic assay; Emergency Treatment - methods; Female; Heart; human serum albumin; Humans; Male; Mass Screening - methods; Medical sciences; Middle Aged; myocardial ischemia; Myocardial Ischemia - blood; Myocardial Ischemia - complications; Myocardial Ischemia - diagnosis; Prospective Studies; Sensitivity and Specificity; Serum Albumin; Time Factors
• ISSN: 0736-4679; 2352-5029
• DOI: 10.1016/S0736-4679(00)00255-9

We initially observed a phenomenon of reduced in vitro binding of exogenous cobalt [Co(II)] to the N-terminus of human serum albumin (HSA) in emergency chest pain patients with early onset unstable angina and myocardial infarction. We then developed a colorimetric assay to measure cobalt-HSA binding and record the results in absorbance units (ABSU). In a preliminary clinical study of 139 emergency patients with acute chest pain, 99 patients with evidence of myocardial ischemia (Group 1) had elevated assay levels (mean ABSU ± SD; 0.519 ± 0.086) compared to 40 patients (Group 2) with no evidence of ischemia (0.316 ± 0.092) (p < 0.00001). In Group 1, 95 of 99 (96.0%) patients had levels higher than a decision threshold of 0.400 ABSU and in Group 2, 37 of 40 (92.5%) samples had higher cobalt binding capacity (ABSU ≤ 0.400). Further studies are warranted to determine if an assay measuring altered cobalt-HSA binding is a clinically useful diagnostic test to rule out myocardial ischemia.