What is the significant level of creatine phosphokinase (CPK) that indicates myocardial cellular injury?

The significant level of creatine phosphokinase (CPK) that indicates myocardial cellular injury is typically considered to be levels greater than 200. CPK is an enzyme found in the heart, brain, and skeletal muscles, and it plays a crucial role in energy metabolism. When there is damage to the heart muscle, such as in the case of a myocardial infarction (heart attack), CPK is released into the bloodstream, leading to elevated levels.

A threshold of greater than 200 is significant as it indicates that myocardial injury has occurred, triggering the clinician to investigate further for conditions like acute coronary syndrome. Although levels above 100 and even 10 could indicate other forms of muscle injury or stress, they are not specifically indicative of cardiac injury to the extent that levels above 200 are. Thus, using greater than 200 as a benchmark can help healthcare professionals diagnose and treat conditions related to myocardial injury effectively.