Creatine Phosphokinase (CPK) Test (Serum)

CPK values help to diagnose muscle injuries. CPK test is done in cases of :

• Suspected heart attack
• Cardiac muscle injuries to assess the severity like myocarditis.
• In skeletal muscle conditions like polymyosistis where there is chronic muscle inflammation.
• Certain inherited muscle disorders like muscle dystrophies.

In case of a heart attack, depending on when it is done , it can predict the severity of the damage to the cardiac muscle.

CPK levels are performed:

• When there is a possibility of a heart attack.
• To assess cardiac muscle injuries and determine their severity such as myocarditis.
• In diseases of the skeletal muscles such as polymyositis, which cause persistent muscle inflammation.
• In a few inherited muscular conditions, such as muscular dystrophy.

Based on when it is performed during a heart attack, it is possible to estimate the degree of cardiac muscle damage.

CPK test measures the level of Creatinine Phosphokinase (CPK) in the blood. 

The test determines the blood's concentration of creatinine phosphokinase (CPK).

CPK test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer. 

Elevated levels of CPK along with other parameters are indicative of a myocardial infarction (heart attack). CPK levels may also rise in case of muscle inflammations (polymyosistis) and muscular dystrophies. Certain medications and brain conditions may also lead to elevated levels. 
 

Doctors generally arrange a CPK blood test to ascertain the extent of muscle damage in a crisis, such as in the case of a suspected heart attack. CPK may also be ordered for patients likely suffering from muscular dystrophy or polymyositis. Additionally, particular CPK laboratory tests can be used to identify any muscular or tissue damage in the cardiac muscles, central nervous system, or skeletal muscles.

A CPK Total serum test is recommended for those who show symptoms, such as muscle weakness and skin rash or muscle stiffness and pain; in emergencies like a suspected heart attack or stroke; and for prolonged seizures or convulsions. Additionally, specific CPK lab tests may be recommended to determine the extent of muscle damage in the heart, brain, or skeletal muscles.

The CPK blood test does not require any particular preparation. However, if you are regularly taking any prescription medicines or other drugs, you must intimidate your doctor as these may interfere with your test results. Some of these may include:

• Drugs that reduce cholesterol
• Steroids
• Anaesthetics
• Cocaine
• Alcohol
• Amphotericin B

Males often have greater normal CPK levels than females. This is because men have higher muscle mass than women. The normal CPK values for an adult measured in Units per liter (U/L) range as follows:

1. Normal values of CPK in males range from 39 to 308 U/L.
2. Normal values of CPK in females range from 26 to 192 U/L.

The CPK blood test is usually administered in emergencies that include a heart attack, stroke, or brain injury. Based on the findings, doctors may order additional tests to decide the next course of treatment. For example, in case of a suspected heart attack, a troponin test may be recommended. Similarly, in case of a brain stroke, a brain CT scan may be ordered

• Total CPK Test
• Total CK Test
• Creatine kinase test
• Creatine phosphokinase Test