If a patient is taking atorvastatin for complains of fatigue, weakness, and muscle aches in his lower back, arms, and legs for the past three days but has not improved with rest, then a CPK level test should be done to this patient. It is a blood test that determines the level of CPK or creatine phosphokinase that can be found in the blood serum. It is an enzyme which can be found mainly in the muscles. For a healthy adult, the normal range of this enzyme in the blood serum would be 22 to 198 units per liter. When during a CPK test, it was found that it is at a level higher than normal, it would indicate that there is a muscle injury from a chronic disease.
