Which statement regarding total CK levels is accurate?

Total CK, or creatine kinase, levels are relevant in various clinical contexts, particularly in diagnosing muscle and heart-related conditions. The statement that the highest levels of total CK are seen in Duchenne's muscular dystrophy is accurate because this condition involves significant muscle degeneration and damage. As muscle fibers are damaged, they release CK into the bloodstream, leading to markedly elevated levels. Duchenne's muscular dystrophy is characterized by a severe deficiency in dystrophin, leading to progressive muscle weakness and subsequent increased CK levels due to sustained muscle injury.

In contrast, the other statements do not reflect the nuances of CK levels accurately. Strenuous exercise can indeed cause transient increases in CK levels due to muscle microtrauma, while repeated intramuscular injections can also lead to localized muscle damage, thus potentially elevating CK levels as well. Lastly, while total CK can indicate heart injury, it is not highly specific for cardiac conditions since it is also released from skeletal muscle and other tissues. Therefore, the statement about Duchenne's muscular dystrophy most accurately describes a condition where CK levels are significantly elevated.