Formal Name
Creatine Kinase-MB
This article was last reviewed on
This article waslast modified on 9 March 2020.
At a Glance
Why Get Tested?

This test is not in routine use, it was historically used to help diagnose a a heart attack but since been replaced by the superior marker troponin.

When To Get Tested?

No longer in routine clinical use

Sample Required?

A blood sample taken from a vein in the arm

Test Preparation Needed?


On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Creatine kinase (CK) is an enzyme that occurs in three major forms, called isoenzymes:

  • CK-MB (found mostly in heart muscle)
  • CK-BB (found mostly in brain)
  • CK-MM (found in muscles)

CK–MB rises when there is any damage to heart muscle cells. Total CK is routinely available in most laboratories and used to indicate muscle disease.

Accordion Title
Common Questions
  • How is it used?

    CK-MB was once the primary test requested for people who had persistent chest pain to see if the pain was coming from the heart. It has now been replaced by the troponin test, which is more specific and sensitive.

  • When is it requested?

    It is no longer in routine use within the UK. It may rarely be requested if a total CK concentration is raised but no clear source is identified.

  • What does the test result mean?

    Increased CK-MB concentrations can usually be detected in someone with a heart attack about 4-6 hours after the onset of chest pain. The level of CK-MB peaks approximately at 12-24 hours after the onset of chest pain and then returns to normal within about 48-72 hours.

  • Is there anything else I should know?

    CK-MB levels may be increased by extensive trauma to skeletal muscles.