Description
Creatine Kinase–MB
Also known as: CK MB, CPK MB
CK–MB is one of three forms of the enzyme creatine kinase (CK). It is found mainly in heart muscle.
CK-MB blood concentration rises when there is damage to heart muscle cells.
CK–MB levels, as well as total CK levels, are tested in persons who have chest pain to diagnose whether they have had a heart attack.
Since a high total CK could indicate damage to the heart but also to other muscles, CK–MB helps to distinguish between both cases.
If patient has symptoms of having had a heart attack, doctor usually gives the patient a “clot-dissolving” drug. Then CK–MB test can help the doctor tell if the drug worked. When the clot dissolves, CK–MB tends to rise and fall faster. By measuring CK–MB in blood several times, your doctor can usually tell whether the drug has been effective.
CK-MB test is prescribed, along with total CK, in persons with chest pain in order to determine whether the pain is due to a heart attack. It may also be ordered in a person with a high CK to determine whether damage is to the heart or other muscles.
Its concentration is measured by means of analysis of a blood sample drawn from the vein in the arm.
Purpose of the test
To determine if you have had a heart attack and whether certain clot-dissolving drugs are working.
It is prescribed if you have chest pain or other symptoms of a heart attack.
Reference range values
<1 – 5 ng/mL
Abnormal findings
A high value of CK-MB and a ratio of CK–MB to total CK more than 2.5–3 usually means, it is likely that the heart was damaged.
A high CK with a relative index below this value suggests that other muscles were damaged.
If your doctor suspects injury to both heart muscle and skeletal muscle, troponin is a more accurate test for identifying a heart attack.
Trouble breathing leads patient to have to use their chest muscles. Chest muscles have more CK–MB than other muscles, which would raise the amount of CK–MB in the blood.
Kidneys failure can also lead to high CK–MB levels without having had a heart attack.
Chronic muscle disease, low thyroid hormone levels, and alcohol abuse can also increase CK–MB levels.