CK MB test measures the creatine kinase –MB enzyme level in the blood. Creatine kinase also called creatine phosphokinase (CPK) has three different forms in the body. CK-MB is an isoenzyme of creatine kinase and it is mostly found in skeletal muscle, heart, brain and little amounts of it is found in other tissues and organs. If CK enzyme is found high in a blood test we can’t understand its source but CK has different forms according to the organs that is found. % 80-85 of total CK is formed from CK-MM and CK-MM is usually found in skeletal muscle, % 10-15 of it is CK MB and it is found in cardiac (heart) muscle. The other form CK-BB is found in brain, intestines and uterus. CK MB level increases in heart attack and CK-MB form may be helpful to diagnose heart attack.
CK MB production in the body
CK MB is found in cardiac muscle and its level is low in normal conditions. In an heart attack CK MB is excreted to blood circulation from damaged cells and CK MB level starts increasing in blood. CK MB level begins increasing in heart attack, 4-8 hours after the starting of chest pain. Its level reaches maximum level after 12-24 hours and returns to normal within 24-48 hours.
How the CK MB test is done ?
A tube of blood collection is needed for CK MB blood test. Nurse/technician (phlebotomist) will insert a needle into your arm vein and collect a tube of blood for this test. All procedure takes 1-2 minutes, you may feel a little pain during the process only for a few seconds.
Preparation for CK MB test
There is no special preparation for CK MB blood test but some medicines and other factors may affect test result so please inform your doctor about the medicines that you use regular.
Factors that may affect CK MB test result
- Biotin: high level of biotin usage cause increasing in CK MB test so there must be 8 hours between the biotin usage and blood collection
Why the CK MB test is done ?
- To determine the source of increased CK; if it is sourced from skeletal muscle or cardiac muscle
- Diagnosis of heart attack if troponin test is not available, measuring the CK MB level at different times may be helpful for heart attack diagnosis
- Diagnosing the cause of symptoms that are suggesting heart attack like; pain in chest, back, arm or jaw. Nausea and vomiting, extreme fatigue, dizziness, pressure in back, shortness of breath, anxiety, sudden sweating, lightheadedness
CK MB test normal results
These results may change according to the laboratory, test method and the analyser
Men: Less than 6.7 ng/mL
Women: Less than 3.8 ng/mL
High CK-MB result causes
- Heart attack
- Heart muscle damage because of a trauma, accident or other reason
- Open heart surgery
- Carbon monoxide poisoning
- Pulmonary embolism
- Myocarditis; inflammation of heart
- Kidney failure
- Cardiac defibrillation
- Pericarditis; inflammation of sac that surrounds the heart
- Electirical injuries
- Chest trauma