

Creatine Kinase (CK) and Creatine Phosphokinase (C.P.K.) are the same, just different naming.
There are subtypes of the enzyme, namely CK-MB, CK-MM and CK-BB. The different subtypes are found in different tissues of the body. The CK-MB subtype is more associated with the heart muscle and is thus more specific in diagnosis of heart disease.
Measurement of CK-MB is more expensive than CK and is thus not readily available in many laboratories, so the measurement of CK is often used as a screening test for heart disease owing to cost-effectiveness. CK-MB is more specific and is thus a better marker for diagnosis / monitoring.
You may find this webpage helpful as well.

