The Significance of Elevated Serum Enzyme Creatine Kinase as a Biomarker in Musculoskeletal Injury: A Review

: Musculoskeletal injury (MSI) has been found to be associated with the abnormality in the serum enzyme creatine kinase (CK). When skeletal muscle sustains injury from the intense prolonged muscular contractions as a consequence of both pathological and physiological factors, it will cause an imbalance in cellular homeostasis increasing the membrane permeability to leak CK enzyme from cells into blood serum. This subsequent release of serum enzyme profusely into the plasma and not being falsely elevated by haemolysis has made CK the preferable biomarker than other serum enzymes. It is a key enzyme that catalyses the reversible transfer of a phosphoryl group (P) from phosphocreatine, producing ATP and creatine. It forms the core of an energy network found in both mitochondria and cytosol where the energy demands are high. Specifically, CK-MM is the type among major isozymes that is most widely distributed among highly differentiated skeletal muscle tissue. Injuries occur due to trauma, infections or even strenuous exercise to the skeletal muscles often trigger high levels of CK-MM. Thus, it is distinctly regarded as a fundamental biomarker for muscle injury. However, some studies show conflicts for lacking sensitivity and not establishing the proper extent of the injury. Accordingly, based on relevant current evidence and opinions, this review paper attempts to provide comprehensive importance of elevated serum enzyme CK as a biomarker for musculoskeletal injury (MSI) and examine if the elevated concentrations are useful for early detection of MSI.