Adult: Male: 55–170 U/L; SI units: 55–170 U/L. Female: 30–135 U/L;
SI units: 30–135 U/L
Newborn: 68–580 U/L
Isoenzymes
CPK-MM: 100%; CPK-MB: 0%; CPK-BB: 0%
. Red-top tube.
■ CPK is an enzyme critical to intracellular energy.
■ The MB isoenzyme is a cardiac marker (but is not as specific
as troponin). Elevations occur in acute MI and are used in the
diagnosis of MI.
■ CPK-MB ratio to total CPK is calculated to increase diagnostic
accuracy. A ratio of 2.5 correlates with cardiac damage.
■ MM elevations occur in crush injuries, seizures, malignant
hypothermia.
