Main Disease Association
Myopathy

Category
Muscle enzymes

When to Order
* Concern for myositis
* Can be added on to a basic or comprehensive metabolic panel order

What It Means If Positive
* It is NOT SPECIFIC for myositis.
* Different patients can have different “normal” levels of CPK.
* Can increase after intense exercise.
* If very high, concern for muscle breakdown associated with any myopathy: drug-induced myopathy, inflammatory myositis, rhabdomyolysis, etc.

What It Means If Negative
* If normal, usually means it is not myositis.
* Relatively HIGH SENSITIVITY for myositis (so if normal, less likely it’s myositis)
* BUT if high pre-test probability/high suspicion for myositis –> check aldolase levels