A creatine kinase (CK) test is a blood test that measures the amount of creatine kinase in your blood. CK is a type of protein called an enzyme that is mostly found in your skeletal muscles, heart, and brain tissue. A small amount of CK in the blood is normal, but higher amounts can indicate a health problem. Depending on the type and level of CK found, it can mean you have damage or disease of the skeletal muscles, heart, or brain. Elevated CK levels may indicate skeletal muscle, heart, or brain damage or degeneration, either chronic (long-term) or acute (short-term) .

Healthcare providers most often use creatine kinase (CK) tests to diagnose and monitor muscular diseases, injuries, and inflammation (myositis) . A CK test may be ordered when muscle damage is suspected and at regular intervals to monitor for continued damage. Symptoms that may indicate the need for a CK test include muscle pain and/or cramps, muscle weakness, balance problems, numbness, or tingling. CK levels may not peak until up to two days after certain injuries, so you may need to be tested a few times.

To perform a CK test, a healthcare provider will take a blood sample from a vein in your arm using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You dont need any special preparations for a CK test. The amount of CK in the serum is reported in units (U) of enzyme activity per liter (L) of serum, and the normal range is 22 to 198 U/L (units per liter) in a healthy adult.