After an acute myocardial infarction (AMI), when do myoglobin levels return to normal?

Myoglobin is a protein found in muscle tissues, and its levels can be measured to assess muscle injury, including in cases of acute myocardial infarction (AMI). After an AMI, myoglobin is one of the first biomarkers to rise in the blood, typically reaching elevated levels within a few hours after the onset of symptoms.

The return of myoglobin levels to normal typically occurs within 18 to 30 hours post-infarction. This rapid clearance is due to the relatively small size of the myoglobin molecule, which allows it to be filtered quickly by the kidneys. Thus, the correct time frame for myoglobin to normalize aligns with this range, reinforcing its utility as an early marker for diagnosing myocardial infarction.

While other time ranges may suggest similar patterns, they either fall outside this typical return-to-normal period or suggest a longer timeframe than is generally observed with myoglobin levels specifically. Hence, the choice indicating 18-30 hours accurately reflects the expected clinical course after an acute myocardial infarction.