5+ Year Member
Nov 26, 2013
Medical Student
Kaplan explains that CK-MB has been used for MI diagnosis, but troponin is rapidly replacing it. Any particular reason?

I feel like both should be used at the same time to figure out the start point of the MI.

Troponin appears 3 to 6 hours after the onset of symptoms and peaks by 16 hours and remains for a week, whereas CK-MB lasts only about 3 days.

So if troponin is elevated and CK-MB is normal that means the MI is at least 3 days old.

So why would Kaplan say that troponin is rapidly replacing CK-MB?


Oh Crap!!!
7+ Year Member
Nov 26, 2009
La La Land
Resident [Any Field]
From what they taught us in school, cTn I is highly specific & sensitive marker of cardiac m. injury as compared to CKMB. cTn I is not present in skeletal muscle at any developmental stage.
CKMB is primarily used to assess any re-infarction because it goes down early. CKMB is not as specific for MI because even though it is primarily found in cardiac m. small amounts are also found in Skeletal m.

so to detect MI you would want to see the marker which is highly specific/sensitive which is cTnI than CKMB