What is the primary use of creatine kinase (CK) testing?

What is the primary use of creatine kinase (CK) testing?

• A. To monitor liver function
• B. As a marker for skeletal muscle disease
• C. To assess lipid metabolism
• D. For diagnosing diabetes

Answer: (B)

The primary use of creatine kinase (CK) testing is indeed as a marker for skeletal muscle disease. CK is an enzyme found primarily in the heart, brain, and skeletal muscle tissue, and it plays a crucial role in the energy metabolism of these tissues. When there is damage to muscle tissue, CK is released into the bloodstream, leading to elevated levels that can be detected through a blood test. This makes CK a valuable tool in diagnosing and monitoring conditions such as rhabdomyolysis, muscle dystrophies, and myocardial infarctions, where muscle injury occurs.

While other options might seem relevant, they do not align with the primary function of CK testing. For instance, assessing liver function involves testing for different enzymes such as alanine aminotransferase (ALT) or aspartate aminotransferase (AST), which are more indicative of liver cell injury. Evaluating lipid metabolism typically involves lipid panels measuring cholesterol and triglycerides, while diagnosing diabetes usually relies on tests measuring blood glucose levels or hemoglobin A1c. Thus, the use of CK testing is distinctly focused on muscle health and injury.