Does creatine kinase always increase with muscle injury?

Yes?: CPK or ck is elevated in conditions of the muscles ( aldolase, SGOT and ldh too). We use it as screening because it's sensitivity. It may elevate with cholesterol medicines, also with heart attacks and with rhabdomyolysis ( when it is too high in the thousands may cause renal damage). After injury to large muscles ck may get elevated.

Yes: Creatine kinase is an enzyme involved with the sole function of muscles which is contracting. Damage to even the smallest amount of muscle will release creating kinase. While small injuries may release so little that normal tests cannot pick it up, we believe that just like a balloon with a hole, some of it escapes with each injury.