Creatine Kinase (CK)
Testing.com is fully supported by readers. We may earn a commission through products purchased using links on this page. You can read more about how we make money here.
- Also Known As:
- CK
- Total CK
- Creatine Phosphokinase
- CPK

This page was fact checked by our expert Medical Review Board for accuracy and objectivity. Read more about our editorial policy and review process.
-
1
Order Your Test
Online or over the phone
-
2
Find a Lab Near You
Over 3,500 locations to choose from
-
3
Get Your Results
Sent Directly to You
At a Glance
Why Get Tested?
To detect and monitor muscle damage; to help diagnose conditions associated with muscle damage; for heart attack detection, this test has been largely replaced by troponin T and I – markers more specific to cardiac tissue; however, it may sometimes be used to help detect a second or subsequent heart attack.
When To Get Tested?
When you have muscle weakness, muscle aches, and/or dark urine and your healthcare practitioner suspects muscle damage; sometimes to monitor for muscle injury resolution or persistence
Sample Required?
A blood sample drawn from a vein in your arm
Test Preparation Needed?
None
You may be able to find your test results on your laboratory’s website or patient portal. However, you are currently at Testing.com. You may have been directed here by your lab’s website in order to provide you with background information about the test(s) you had performed. You will need to return to your lab’s website or portal, or contact your healthcare practitioner in order to obtain your test results.
Testing.com is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.
The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.
If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test(s) to obtain the reference range.
Laboratory test results are not meaningful by themselves. Their meaning comes from comparison to reference ranges. Reference ranges are the values expected for a healthy person. They are sometimes called “normal” values. By comparing your test results with reference values, you and your healthcare provider can see if any of your test results fall outside the range of expected values. Values that are outside expected ranges can provide clues to help identify possible conditions or diseases.
While accuracy of laboratory testing has significantly evolved over the past few decades, some lab-to-lab variability can occur due to differences in testing equipment, chemical reagents, and techniques. This is a reason why so few reference ranges are provided on this site. It is important to know that you must use the range supplied by the laboratory that performed your test to evaluate whether your results are “within normal limits.”
For more information, please read the article Reference Ranges and What They Mean.
What is being tested?
Creatine kinase (CK) is an enzyme found in the heart, brain, skeletal muscle, and other tissues. Increased amounts of CK are released into the blood when there is muscle damage. This test measures the amount of creatine kinase in the blood.
The small amount of CK that is normally in the blood comes primarily from skeletal muscles. Any condition that causes muscle damage and/or interferes with muscle energy production or use can cause an increase in CK. For example, strenuous exercise and inflammation of muscles, called myositis, can increase CK as can muscle diseases (myopathies) such as muscular dystrophy. Rhabdomyolysis, an extreme breakdown of skeletal muscle tissue, is associated with significantly elevated levels of CK.
Common Questions
Health Professionals – LOINC
LOINC Observation Identifiers Names and Codes (LOINC®) is the international standard for identifying health measurements, observations, and documents. It provides a common language to unambiguously identify things you can measure or observe that enables the exchange and aggregation of clinical results for care delivery, outcomes management, and research. Learn More.
Listed in the table below are the LOINC with links to the LOINC detail pages. Please note when you click on the hyperlinked code, you are leaving Testing.com and accessing Loinc.org.
LOINC | LOINC Display Name |
---|---|
2157-6 | CK [Catalytic activity/Vol] |
50756-6 | CK (Bld) [Mass/Vol] |
View Sources
Sources Used in Current Review
2016 review performed by Hari Nair, PhD, DABCC, FACB, Technical Director, Boston Heart Diagnostics and the Editorial Review Board.
(Update December 22, 2015) National Institute of Neurological Disorders and Stroke. Myopathy Information Page. Available online at http://www.ninds.nih.gov/disorders/myopathy/myopathy.htm. Accessed June 2016.
(Update 9/22/2015) Silberberg C. Rhabdomyolysis. MedlinePlus Medical Encyclopedia. Available online at https://www.nlm.nih.gov/medlineplus/ency/article/000473.htm. Accessed June 2016.
(January 31, 2000) Muscular Dystrophy Association. Simply Stated: The Creatine Kinase Test. Available online at https://www.mda.org/quest/article/simply-stated-the-creatine-kinase-test. Accessed June 2016.
Cabaniss, C.D. Creatine Kinase. H.W. Walker HK, Hurst JW. Clinical Methods: The history, Physical, and Laboratory Examinations. Boston: Butterworths; 1990. 32.
(December 27, 2015) Bethel C. Myopathies. Medscape Review. Available online at http://emedicine.medscape.com/article/759487-overview. Accessed June 2016.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp. 306-309.
MedlinePlus Medical Encyclopedia: CPK. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003503.htm. Accessed February 2009.
Zieve, D. (Updated 2012 September 14). Creatine phosphokinase test. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003503.htm. Accessed December 2012.
Junpaparp, P. et. al. (Updated 2012 November 28). Creatine Kinase. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2074023-overview. Accessed December 2012.
Schreiber, D. and Miller, S. (Updated 2011 March 29). Use of Cardiac Markers in the Emergency Department. [On-line information]. Available online at http://emedicine.medscape.com/article/811905-overview. Accessed December 2012.
(© 1995-2012). Creatine Kinase (CK), Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/8336. Accessed December 2012.
Lehman, C. and Meikle, A. (Updated 2012 November). Ischemic Heart Disease. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/IHD.html?client_ID=LTD. Accessed December 2012.
Pagana, K. D. & Pagana, T. J. (© 2011). Mosby’s Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 322-325.
Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pp 300-303.
McPherson, R. and Pincus, M. (© 2011). Henry’s Clinical Diagnosis and Management by Laboratory Methods 22nd Edition: Elsevier Saunders, Philadelphia, PA. Pp 439-440.
Dugdale, D. (Updated 2011 September 19). Rhabdomyolysis. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000473.htm. Accessed January 2013.
Bethel, C. (Updated 2012 March 9) Myopathies. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/759487-overview. Accessed January 2013.
Do, T. (Updated 2012 September 21). Muscular Dystrophy. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1259041-overview. Accessed January 2013.
Eyal Muscal, E. and Morales DeGuzman, M. (Updated 2012 June 22). Rhabdomyolysis. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/1007814-overview. Accessed January 2013.
National Institute of Neurological Disorders and Stroke. NINDS Kennedy’s Disease Information Page. Available online at http://www.ninds.nih.gov/disorders/kennedys/kennedys.htm. Accessed November 2014.
Barkhaus, PE et al. Kennedy Disease Workup. Medscape. Available online at http://emedicine.medscape.com/article/1172604-workup. Accessed November 2014.
Better Health Channel. Kennedy’s disease. Available online at http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Kennedy’s_disease. Accessed November 2014.
Ask a Laboratory Scientist
