Macro-CK or IgG-bound CK1 is associated with an apparent increase in which CK isoenzyme?

Macro-CK or IgG-bound CK1 is associated with an apparent increase in which CK isoenzyme?

• A. Macro-CK / IgG bound CK1
• B. CK-MM
• C. CK-MV
• D. CK-BB

Answer: (A)

Macro-CK is a macroenzyme formed when CK binds to an immunoglobulin, usually IgG. This complex has a larger size and altered behavior in CK isoenzyme assays, so its activity is often detected at the position of the CK1 (IgG-bound CK) fraction. In other words, the presence of this CK–IgG complex makes the CK1 category appear elevated, even though the true CK-MM, CK-MB, or CK-BB levels haven’t independently risen. That’s why the apparent increase is in the CK1 (IgG-bound CK) isoenzyme.

Macro-CK is a macroenzyme formed when CK binds to an immunoglobulin, usually IgG. This complex has a larger size and altered behavior in CK isoenzyme assays, so its activity is often detected at the position of the CK1 (IgG-bound CK) fraction. In other words, the presence of this CK–IgG complex makes the CK1 category appear elevated, even though the true CK-MM, CK-MB, or CK-BB levels haven’t independently risen. That’s why the apparent increase is in the CK1 (IgG-bound CK) isoenzyme.