Abnormal cpk levels can be due to various reasons. CPK levels are comparatively high in the skeletal muscle, heart and the brain. So any damage to skeletal muscle heart or brain can give rise to abnormal cpk levels. But in the clinical setting the most important aspects are the skeletal muscles and the heart. In the case of abnormal cpk levels in the clinical setting the term “Abnormal cpk levels” is synonymous with elevated cpk levels. (See also - elevated cpk levels) when we talk about the skeletal muscle conditions direct trauma, exercise, polymyositis, dermatomyositis, Duchenne muscular dystrophy and etc can give rise to very high cpk values. In Duchenne muscular dystrophy cpk values can be abnormal (very high) even before the actual clinical manifestation.
After a myocardial infarction damaged myocardial cells release cpk-mb isoform of the CPK enzyme. This can give rise to abnormal CPK levels in the blood. But significance of this decreases after two days. But in addition to these many other conditions can give rise to abnormal cpk levels. So before coming to a conclusion all the differential diagnosis of a particular clinical scenario should be taken into account.