Creatinine phosphokinase, or CPK, is an enzyme that is found only in the heart, brain and skeletal muscle, as stated by MedlinePlus. High levels of the CPK enzyme are not found in the liver itself, but the test allows doctors to discover muscle injury or disease, heart attack or infection.
It is common for some patients to have a high CPK test result along with a high liver enzyme count, according to Quest. An elevated CPK level along with elevated liver enzymes, such as ALT or AST indicates that there is an issue with the muscle in the body, rather than the liver. A low CPK level with elevated liver enzyme levels is more indicative of a problem with the liver itself, although high enzyme levels are not always a sign of a serious health issue. High liver enzyme levels indicate that the liver is leaking these enzymes into the blood, and high CPK levels indicate that creatinine phosphokinase is being leaked into the blood by the heart, brain or muscles.
A damaged liver may occur for many reasons; the use of recreational or over-the-counter liver damaging drugs, the contraction of hepatitis, occurrence of malignancy, or when someone eats contaminated shellfish, according to Quest.