Troponin-T is preferable to CPK-MB in the diagnosis of acute MI in all of the following situations except ?

Ans. is 'c' i.e., Reinfarction after 4 dayso Troponin levels are elevated for 7-10 days after MI.o If reinfarction occurs within 4 days of first infarction, one cannot differentiate whether the troponin is raised due to first infarct or due to recent one.o On the other hand, CPK-MB levels return to normal within 72 hours. So, after 3 days of previous infarct, it can be used.