the most sensitive double-marker method of cardiac isoenzymes of creatinine kinase, troponin i, and myoglobin in different time periods for diagnosing acute myocardial infarction

purpose: myocardial infarction is among the most common diagnoses in patients admitted   to hospitals in western countries, and its rapid diagnosis is of utmost importance. this study   was conducted to determine the most sensitive double-marker cardiac isoenzyme of creatinine   kinase, troponin i, and myoglobin for diagnosing acute myocardial infarction.   materials and methods: this was an observational-analytic research on a diagnostic test   conducted on 256 patients who had referred to the emergency department with chest pain from   4 to 24 hours before their referral. they were sorted equally into two groups of 4-14 hours and   15-24 hours from onset of pain, each group including 128 patients.   results: in the first time period, the combination of troponin and myoglobin had the highest   sensitivity (sensitivity = 97.3%, specificity = 98.1%), whereas the combination of double-marker   and troponin proved the most sensitive (sensitivity = 100%, specificity = 96.3%).   conclusion: the double-marker combination of troponin and myoglobin is more appropriate   for the first time period (i.e. during the first 24 hours from the onset of chest pain),while it   would be more helpful to use the combination of troponin during the second period of time .