How many hours does it usually take for CK-MB to return to normal levels after an infarction?

After a myocardial infarction, the creatine kinase MB (CK-MB) enzyme levels typically rise in the blood as a result of cardiac tissue damage. The peak usually occurs within 24 hours after the onset of chest pain, and subsequently, the levels start to decline.

CK-MB generally returns to normal levels approximately 48 to 72 hours after the infarction. It's key to note that the timing can vary based on individual patient factors and the extent of the infarction, but 48 hours is commonly cited as the timeframe for many patients to expect CK-MB levels to normalize after the peak elevation post-infarction. Hence, the best choice reflects this typical timeline for CK-MB return to baseline levels.