Why do we measure CPK in rheumatology labs?

Why do we measure CPK in rheumatology labs?

• A. To assess muscle involvement such as polymyositis
• B. To evaluate kidney function
• C. To measure liver enzymes
• D. To assess coagulation

Answer: (A)

Measuring CPK in rheumatology labs is about detecting and tracking muscle involvement. CPK is an enzyme released from damaged skeletal muscle, so when inflammatory muscle diseases like polymyositis or dermatomyositis are active, serum CPK rises. Checking its level helps confirm that muscle is being affected and, importantly, provides a way to monitor disease activity and response to therapy over time. The test targets skeletal muscle injury (the CK-MM form is the main contributor in these conditions), rather than liver, kidney, or coagulation function. Be mindful that factors like recent intense exercise, muscle trauma, or certain medications (for example, statins) can also raise CPK, which should be considered when interpreting results.

Measuring CPK in rheumatology labs is about detecting and tracking muscle involvement. CPK is an enzyme released from damaged skeletal muscle, so when inflammatory muscle diseases like polymyositis or dermatomyositis are active, serum CPK rises. Checking its level helps confirm that muscle is being affected and, importantly, provides a way to monitor disease activity and response to therapy over time. The test targets skeletal muscle injury (the CK-MM form is the main contributor in these conditions), rather than liver, kidney, or coagulation function. Be mindful that factors like recent intense exercise, muscle trauma, or certain medications (for example, statins) can also raise CPK, which should be considered when interpreting results.