Management of Elevated CK-MB in Patients on Clozapine

Understanding the Clinical Context

The American College of Cardiology recommends troponin as the preferred and most specific biomarker for myocardial injury, not CK-MB, due to its nearly absolute myocardial tissue specificity 1, 2
Cardiac troponin has nearly absolute myocardial tissue specificity and is the gold standard for detecting myocardial necrosis, while CK-MB is less tissue-specific and can be elevated from non-cardiac sources 1, 2
An elevated CK-MB in the absence of elevated troponin should prompt a search for other causes rather than automatically indicating myocardial injury 1
In the clinical setting of acute ischemia, myocardial infarction is diagnosed when both sensitive biomarkers like troponin AND CK-MB are increased together—not CK-MB alone 1

The European Heart Journal suggests that troponins will clarify any cardiac involvement when CK-MB is falsely elevated 3
The American College of Cardiology recommends that measurement of total CK is not recommended for routine diagnosis of acute MI due to wide tissue distribution 1, 2
Elevated biomarkers in the absence of clinical evidence of ischemia should prompt a search for other causes rather than assuming cardiac damage 1

The American College of Cardiology advises against relying on CK-MB alone when cardiac troponin assays are available, as troponin is far more sensitive and specific 1, 2, 4