116 MCQs in Pathology Answer

The Correct option is C


CK–MB levels, along with total CK, are tested in persons who have chest pain to diagnose whether they have had a heart attack. Since a high total CK could indicate damage to either the heart or other muscles, CK–MB helps to distinguish between these two sources.

The CK and CK index (a calculated parameter that evaluates the amount of CK-MB relative to the amount of total CK) rapidly rise together in a time course consistent with acute myocardial infarction (AMI).

Even at 8 hours, the laboratory suggests myocardial injury.

In AMI, CK-MB makes up a high percentage of total CK, so the CK index rises with CK-MB. In skeletal muscle injury, CK can be very high, but CK-MB is only a tiny portion of the total CK, so the CK index stays low. Serum CK is only slightly elevated on admission.

The time course of CK elevation is consistent with that expected for infarct-related release of CK. CK-MB rises and falls in parallel with CK, as does the CK index, with a peak at 24 hours. In this case, total CK and CK-MB appear to peak at the same time.

In most cases, CK-MB peaks about 6 hours before total CK and returns to normal levels about 12-24 hours before total CK.

Category: Pathology MCQs