Which biochemical test indicates a depleted muscle mass?

Creatinine kinase (CK) test

Creatine kinase (CK) is an enzyme primarily found in skeletal muscle and cardiac muscle. It plays a crucial role in energy metabolism by catalyzing the conversion of creatine to phosphocreatine, a high-energy molecule that provides energy for muscle contractions. When muscle tissues are damaged or injured, CK is released into the bloodstream. As a result, elevated CK levels in the blood can be an indication of muscle damage and may suggest muscle loss.

When there is a depletion of muscle mass, such as in conditions like sarcopenia or muscular dystrophy, the levels of CK in the blood may be lower than normal.

Therefore, a low CK test result can be an indicator of depleted muscle mass. However, it's important to interpret CK test results in the context of the individual's overall health and other relevant clinical information, as CK levels can also be affected by other factors such as recent strenuous exercise or certain medications.