Creatine Kinase and Isoenzymes
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CK and isoenzymes.
To monitor myocardial infarction and some disorders of the musculoskeletal system such as Duchenne’s muscular dystrophy.
Serum collected in a red- or red/gray-top tube. Serial specimens are highly recommended. Care must be taken to use the same type of collection container if serial measurements are to be taken.
(Method: Enzymatic for CK, electrophoresis for isoenzymes; enzyme immunoassay techniques are in common use for CK-MB)
|Conventional & SI Units|
|Newborn–1 yr||Up to 2 × adult values|
|Male (children and adults)||50–204 units/L|
|Female (children and adults)||36–160 units/L|
|CK Isoenzymes by Electrophoresis|
|CK-MB by Immunoassay||0–5 ng/mL|
|CK = creatine kinase; CK-BB = CK isoenzyme in brain; CK-MB = CK isoenzyme in heart; CK-MM = CK isoenzyme in skeletal muscle.The CK-MB index is the CK-MB (by immunoassay) divided by the total CK and then multiplied by 100. For example, a CK-MB by immunoassay of 25 ng/mL with a total CK of 250 units/L would have a CK-MB index of 10.Elevations in total CK occur after exercise. Values in older adults may decline slightly related to loss of muscle mass.|