Alternate Names : Creatine Kinase-Isoenzymes, Creatine Phosphokinase-Isoenzymes, CK-Isoenzymes
This test measures the blood levels of three forms of the enzyme
creatine phosphokinase, which is also called CPK. These forms are known as
isoenzymes. They are called CPK-BB, CPK-MB, and CPK-MM.
This blood test determines the amounts of each of these
isoenzymes in the blood. These levels can help a doctor to diagnose certain
illnesses and conditions.
CPK-BB is found mainly in the brain and lungs.
CPK-MB is found mainly in the heart.
CPK-MM is found mainly in skeletal muscle.
Damage to the brain, lungs, heart, or muscle may cause the
corresponding isoenzyme to leak into the bloodstream.
How is the test performed?
In order to measure the amount of CPK isoenzymes in the blood,
a blood sample is taken from a vein on the forearm or hand. First, the skin over
the vein is cleaned with an antiseptic. Next, a rubber tube called a tourniquet is
tied around the upper arm. This enlarges the veins in the lower arm by restricting
blood flow through them. A fine needle is gently inserted into a vein, and the
tourniquet is removed. Blood flows from the vein through the needle and is
collected in a syringe or vial for testing in the laboratory. After the needle is
withdrawn, the puncture site is covered for a short time to prevent bleeding.