Serum Creatinine Phosphokinase (CPK) – Mass Concentration

What Is Creatine Phosphokinase (CPK)?

Creatine phosphokinase (CPK), also called creatine kinase, is an enzyme that helps convert phosphocreatine into ATP (energy) in cells. It’s naturally present in heart, skeletal, and brain tissues. When cells are damaged—such as from a heart attack, muscle injury, or stroke—the enzyme leaks into the bloodstream, raising CPK levels. This test helps doctors evaluate conditions affecting these organs.

Why Might You Need This Test?

Your doctor may order CPK testing if you have symptoms like chest pain, muscle weakness, or unexplained fatigue. It’s also used to monitor conditions like heart disease, muscle disorders, or after trauma/injury. In some cases, it helps diagnose nerve or muscle diseases.

When Are CPK Levels Abnormal?

Elevated CPK levels (above normal) may indicate recent muscle damage, heart problems, or other conditions like myositis (inflammation of muscles) or certain neurological disorders. However, CPK alone isn’t diagnostic—your doctor will consider symptoms and other test results.

What Can Affect CPK Levels?

Factors like strenuous exercise, muscle injuries, infections, or certain medications can temporarily raise CPK. Smoking, alcohol use, or dehydration may also influence results. Always discuss your full medical history with your provider.