ABSTRACT
Objective: To assess the accuracy of B-type natriuretic peptide (BNP) in addition to myoglobin, creatine kinase-MB (CK-MB), and troponin I to diagnose patients with non ST-segment elevation myocardial infarction (NSTEMI) at the emergency department. Methods: During January to July 2007, a total of 100 patients with suspected acute myocardial infarction at the emergency department were included. 50 were classified as NSTEMI and 50 as non-NSTEMI according to the final hospital diagnosis. Blood samples for investigation of myoglobin, CK-MB, troponin I, and BNP analysis were collected in EDTA tubes concomitantly with routine blood specimens from the emergency department and measured by Biosite Triage Cardioprofiler Panel (Biosite Inc., San Diego, CA) Results: The diagnostic sensitivity of Myoglobin and BNP (cut-off value of 100 pg/mL) for acute myocardial infarction (AMI) was significantly higher than CK-MB and troponin-I at the emergency department (76 and 82 vs. 36 and 24 %, respectively, P< 0.001). BNP in addition to myoglobin, CK-MB, and troponin I improved the diagnostic sensitivity from 86% to 100%. The optimum cut-off point levels for myoglobin, CK-MB, troponin-I, and BNP were 150 ng/mL, 3.8 ng/mL, 0.15 ng/mL and 147 pg/mL respectively. Using the optimal cutoff point, the sensitivity was 96 % and specificity was 46 % in diagnosis for myocardial infarction. Conclusion: Multiple cardiac markers by use of quantitative point-of-care testing for myoglobin, CK-MB, troponin-I and BNP are useful for ruling out patients presenting to the emergency department with suspected NSTEMI.