What is the most likely reason for the abnormal rise in myoglobin levels after admission in the presence of elevated troponin and CK-MB?

The most likely reason for the abnormal rise in myoglobin levels after admission, especially when accompanied by elevated troponin and CK-MB levels, typically indicates an actual pathological process rather than sample handling issues. It suggests that there is a physiological response occurring rather than a laboratory error.

When considering the possibility that the patient did not suffer a myocardial infarction until after admission, it becomes clear that elevated troponin and CK-MB levels point to myocardial injury, which can be concurrent with rising myoglobin levels. Ideally, myoglobin should rise early after muscle damage, even before troponin. Therefore, a late rise in myoglobin following an established injury, indicated by the elevated troponin and CK-MB, would correspond with the timing of myocardial infarction.

If hemolysis were an issue, it could certainly interfere with lab results; however, hemolysis typically affects plasma levels of various markers in ways that would not necessarily correlate with established patterns of myocardial injury.

As for unstable angina, this condition does not cause troponin elevation since it is characterized by insufficient blood flow to induce myocardial necrosis, which would otherwise lead to expected elevations of troponin and CK-MB.

Given these considerations, the most fitting conclusion aligns