Which enzyme is a definitive measure for skeletal muscle disorders?

• A. LD
• B. CK
• C. ALP
• D. Amylase

Answer: (B)

The enzyme that serves as a definitive measure for skeletal muscle disorders is creatine kinase (CK). CK is predominantly found in skeletal muscle, heart muscle, and the brain, but its isoenzyme CK-MM is specific to skeletal muscle. When there is muscle damage or myopathy, CK levels in the blood can elevate significantly due to the release of this enzyme from the damaged muscle fibers into circulation.

Elevated CK levels are particularly indicative of conditions such as muscular dystrophy, rhabdomyolysis, and other myopathic disorders, making it a key biomarker in the diagnosis and management of skeletal muscle issues. Measuring CK levels can help clinicians assess the extent of muscle damage and monitor changes over time as a part of patient care.

Other enzymes mentioned, such as lactate dehydrogenase (LD) and alkaline phosphatase (ALP), can elevate in various conditions but are not specific to muscle disorders. For instance, LD can indicate tissue damage related to various organs, including liver and heart, while ALP is primarily associated with liver and bone conditions. Amylase is typically associated with pancreatic function and is not relevant to skeletal muscle disorders. Thus, CK’s strong correlation with muscle damage makes it the enzyme of choice for identifying and assessing