Serum Creatinine Phosphokinase (CPK) or Creatine Kinase (CK) Activity

What Does CPK/CK Measure?

Creatine kinase (CK) is released into the bloodstream when muscle, heart, or nerve cells are injured. The test quantifies this enzyme’s activity, which can indicate recent trauma to these tissues. Higher levels may suggest conditions like heart attacks, muscle strains, or neurological events.

Why Is This Test Done?

Doctors order CPK/CK tests to diagnose or monitor conditions such as heart attacks (myocardial infarction), muscle injuries (e.g., from overexertion or trauma), or neurological disorders. It may also be used in sports medicine to evaluate muscle damage post-exercise.

Common Conditions Monitored

Elevated CPK/CK levels are often seen in acute heart attacks, rhabdomyolysis (severe muscle breakdown), stroke, or conditions like myopathy (muscle diseases). Low levels may be normal or indicate certain muscle disorders, but they’re less commonly clinically significant.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in the arm. The sample is processed into serum (liquid remaining after blood clotting) for testing. No special preparation is needed, but fasting may be advised depending on the clinical context.