Cardiac Bioniarker-OiChoice for diagnosis of Myocardial Infarction 10 days after the initial event:

Answer is A (Troponins) Cardiac Troponins are the biomarkers of choice for detection of Acute Myocardial Infarction. The enzymes troponin I and troponin T are normal proteins impoant in the contractile apparatus of the cardiac myocytes. They are released into the circulation about 4-8 hours after myocardial infarction and are still detectable for 10-14 days after the initial event. The long half-life allows for the late diagnosis of myocardial infarction (however makes it difficult to detect re-infarction as can occur in acute stent thrombosis after percutaneous coronary intervention). Preferred Markers for Detection of Acute Myocardial Infarction (Specific) Enzyme Seen at Peaks at Returns to normal after Other features Creatinine phosphokinase (MB 4 to 8 hours 24 hrs 48-72 hrs * Very sensitive test * Less specific than troponins (also increase in skeletal muscle injury) Isoenzyme) * Test of choice for detecting recurrent ischemic event in 4 to 10 day window Troponin 1 4 to 8 hours 48 hours 7-10 days * Very Sensitive test (Sensitivity similar CPK-MB) * Very Specific test (More specific than CPK-MB). Troponin T 4 to 8 hours 48 hours 10-14 days * Test of choice for detecting Acute Myocardial Infarction (Earl)' diagnosis and Late Diagnosis) * Less useful for detecting re-infarction since troponins may remain elevated for 10-14 days making it Non Specific Markers for Detection of Acute Myocardial Infarction ( Not Preferred) Enzyme Seen at Peaks at Returns to normal after Other features Myoglohin 30 minutes to 2 hours 4-6 hours 10 to 12 hours Earliest Marker to be raised Not specific for MI Lactate dehydrogenase 24 hrs 4-5 days 10 days Not Specific AST or SGOT Within 12 hrs 48 hrs 4-5 days Not specific