Assay of ischemia‐modified albumin and C‐reactive protein for early diagnosis of acute coronary syndromes

Abstract

Diagnosis of cardiac ischemia in patients coming to emergency departments (ED) with symptoms of acute chest pain is often difficult. Many markers are sensitive and specific for the detection of myocardial necrosis but may not rise during reversible myocardial ischemia. Ischemia‐modified albumin (IMA) has recently been shown to be a sensitive and early biochemical marker of ischemia. The variation laws were observed by measuring IMA and C‐reactive protein (CRP) of 113 patients in ED within 12 hr after onset of chest pain. In the observation, blood was taken for IMA and CRP. Patients underwent standardized triage, diagnostic procedures, and treatment. Results of IMA and CRP were correlated with final diagnoses of nonischemic chest pain (NICP) and acute coronary syndrome (ACS). There were obvious distinction of IMA and CRP levelsbetween the NICP and ACS groups. Receiver operator characteristic (ROC) curve analysis was used to determine the optimal cutoff of this assay for identifying individuals with ACS patients from NICP. The area under the curves of IMA is 0.948. The sensitivity and specificity of albumin cobalt binding (ACB) at a cutoff value of 70.0 units/mL were 94.4% and 82.6%, respectively. The area under the curves of CRP is 0.746. Sensitivity and specificity of CRP at a cutoff value of 3.16 mg/L were 70.0% and 73.9%, respectively. Negative predictive value (NPV) of IMA and CRP for ischemia origin was 79.2% and 38.6%, respectively. IMA may make an early diagnosis of acute coronary ischemia, and will improve the early diagnostic sensitivity and specificity of ACS. J. Clin. Lab. Anal. 22:45–49, 2008. © 2008 Wiley‐Liss, Inc.