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McMaster Textbook of Internal Medicine

Creatine Kinase (CK) and Creatine Kinase–MB Fraction (CK-MB)

How to Cite This Chapter: Don-Wauchope A, Chetty VT, Ivica J, Kavsak P, Khan WI, Lafreniere M, Nouri K, Solnica B. Creatine Kinase (CK), Creatine Kinase–MB Fraction (CK-MB). McMaster Textbook of Internal Medicine. Kraków: Medycyna Praktyczna. https://empendium.com/mcmtextbook/chapter/B31.1269.3.7.109. Accessed December 05, 2025.
Last Reviewed: May 9, 2022
Last Updated: May 9, 2022
Chapter Information

For a brief introduction and guide to abbreviations, see Laboratory Tests: General Remarks.

Analyte [material]

Creatine kinase (CK) [S/P], creatine kinase–MB fraction (CK-MB) [S/P]

Reference range, target level, or decision threshold

CK: 24-195 U/L in men, 24-170 U/L in women!!!; CW

CK-MB <12 U/L (not recommended as test)!!!; CW

Interpretation of results

↑ Skeletal muscle injury: Trauma, IM injections, strenuous exercise, seizures, myositis (eg, polymyositis), muscular dystrophies, myotonias, drugs (statins, fibrates, neuroleptics), illicit drugs (heroin, amphetamines), alcohol intoxication, carbon monoxide poisoning, myocardial diseases (MI, myocarditis), PE; results may be overestimated due to macromolecular enzyme isoforms (macro-CK)

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