What are the Purpose and Range of the CPK test

CPK Test: Process, Purpose and Normal Range

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Creatine Phosphokinase (CPK) test is also called the creatine kinase (CK) test. This is a blood test, which detects the amount of CPK enzyme in the body. It is mainly found in the (brain, cardiac and skeletal muscles). It helps our muscles to function properly. High levels of CPK in the blood indicate muscle damage.

CPK is usually found in very small amounts in the blood. However, any damage to the muscles or any disturbance in the production of energy by the muscles increases its level.

There are some conditions that result in muscle damage, such as swelling, myopathy (muscular dystrophy), over-exercising, and muscle breakdown (Rhabdomyolysis, a disease characterized by muscle breakdown and high levels of CPK) etc.

Why CPK test is done – What is the purpose of the CPK test

The CPK test is performed when muscle damage is suspected or the person shows signs of a muscle injury.

These symptoms include the following:

  • muscle pain
  • muscle weakness
  • trouble moving muscles
  • muscle cramps
  • muscle pain and stiffness
  • Dark-colored urine (the color of urine becomes thick in myoglobin disease, a substance secreted by damaged muscles and can affect the kidneys)

This test is done at regular intervals to monitor the condition of the damage. Apart from this, it is also very helpful in testing for myopathy (muscular dystrophy) and trauma (such as burns or excessive pressure on the muscles), etc.

There are three isoenzymes of CPK that are present in different places in the body and they help to identify the area of ​​damage:

  • CPK-MB (found in the heart muscle)
  • CPK-MM (found in skeletal muscles)
  • CPK-BB (found in the brain)

What is the Creatine Kinase Isoenzyme MB (CK-MB) Test?

Creatine kinase is also called creatine phosphokinase (CPK). It is an enzyme found mainly in the heart and skeletal muscles. Skeletal muscles are the muscles related to the skeletal system. CPK is also found in small amounts in the brain. It is secreted into the blood during an injury, stress, or muscle damage.

Full formCreatine Phosphokinase test
Test typeEnzyme based test
Normal range10-120 mcg/L
PurposeTo detect Heart disease, Kidney disease or rhabdomyolysis etc
Major elementsCreatine, Adenosine triphosphate (ATP), Phosphocreatine (PCr), and Adenosine diphosphate (ADP)

The CK-MB test is usually done to test for myocardial infarction or heart attack. CK-MB is present inside the body in two forms. CK-MB2 is secreted by cardiac cells and converted into CK-MB1 in the blood. It helps in accurate diagnosis of myocardial infarction if done early, within 6 hours of the appearance of cardiac symptoms.

CPK Test - Creatine Phosphokinase Test
Creatine Kinase Isoenzyme MB (CK-MB) Test

Test results can be confirmed by medical examination and evaluation of other cardiac biomarkers. A cardiac biomarker is a specific test that specifically evaluates the functions of the heart.

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Before CPK test

It is done like a normal blood test, so no special preparation is required before getting this test done.

During CPK test

This is a simple test that takes less than five minutes. An experienced doctor will take a blood sample by inserting a needle into a vein in your arm. A small amount of blood is drawn into a test tube, then the tube will be closed and sent to a lab for testing. You may feel slight pain when the needle is inserted into the vein.

Apart from this, there may be a slight danger of pain, dizziness, and bruising at the needle site. However, most of these symptoms disappear soon. Occasionally, the infection can occur from the bleeding site. If the symptoms persist for a long time, then inform the doctor about it.

Test Result and Normal Range

CPK levels are written in micrograms per liter (mcg/L).

CPK Test - Creatine Phosphokinase Test
Test Result and Normal Range #NCERT SOLUTIONS

CPK Test Normal results

The normal result for CPK test is 10-120 mcg/L.

Unusual results

High levels of CPK are seen in the following cases:

  • Recent injury or trauma (such as a burn)
  • Muscular dystrophy
  • Strenuous exercise (exercises that put excessive stress on the body)
  • Brain injury or stroke
  • Memory problem (delirium tremens)
  • Polymyositis
  • Long-term surgery
  • Endocrine disorders (thyroid disease, Cushing’s syndrome or Addison’s disease)
  • Seizure
  • Connective tissue disorders (Like – systemic lupus or rheumatoid arthritis)
  • Celiac disease
  • Viral, bacterial or parasitic infection
  • Kidney failure
  • Chills or shivering with fever
  • Thrombosis (blood clotting in a blood vessel)
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The amount of CPK normally increases during or after strenuous exercise, prolonged exercise, and sports.

People who have high muscle density are found to have more CPK, so it is more in men than in women. Any injury to the muscle, such as a puncture in an injection, can also temporarily increase CPA levels. CPK levels are low in the early stages of pregnancy.

CPK test is done to detect the recent heart attack but is now done by the troponin eye test. However, once a heart attack recurs soon after this test can be done to check for this condition. CPK is usually done in conjunction with other tests, including electrolyte levels, blood urea nitrogen, creatinine levels, and urine myoglobin levels (when rhabdomyolysis disease is suspected).

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