CPK isoenzymes are broken down into three parts: CPK-1 from the brain and lungs; CPK-2 from the heart; and CPK-3 from skeletal muscles, explains Healthline. A CPK test is used to derive total creatine phosphokinase levels in blood. The normal range is 10 to 120 micrograms per liter, states MedlinePlus.
A CPK test may be used to diagnose a heart attack, determine the cause of chest pain, detect muscle diseases such as dermatomyositis and polymyositis, and determine the extent of the damage to a muscle, according to MedlinePlus. Some drugs, such as steroids, anesthetics, amphotericin B, alcohol, cocaine and those used to lower cholesterol, may interfere with the test results, notes Healthline. Therefore, patients should inform their doctors of any prescribed medications or current drug use before having the test done to ensure accurate test results.
The individual levels of the different types of CPK are used to determine the condition with which patients might be afflicted. Elevated levels of CPK-1 may indicate brain injury, brain cancer, or stroke or death of an area of the lung. High CPK-2 levels might be indicative of injury to the heart, inflammation of heart muscles or electrical injuries, while escalated levels of CPK-3 may indicate muscular dystrophy, muscle trauma or electromyography, explains Healthline.