Creatine Kinase (CK) Test

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KEY POINTS

• This blood test measures an enzyme called creatine kinase (CK) or creatine phosphokinase (CPK). Enzymes are chemicals that help the cells of your child’s body work.
• Don’t let your child exercise or play sports for 24 hours before the test.
• Ask your child’s healthcare provider when and how you will get the results of your child’s test.

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What is the creatine kinase test?

This blood test measures an enzyme called creatine kinase (CK) or creatine phosphokinase (CPK). Enzymes are chemicals that help the cells of your child’s body work. Muscle cells make the creatine kinase enzyme. When muscle cells are injured or diseased, enzymes leak out of the cells and enter the bloodstream.

This test is also called a total CK test.

Why is this test done?

The CK test may be done to check for muscle injury or disease. Other blood tests may be needed to find out exactly what the problem is.

The test may be done to:

• Look for sports or muscle injuries and give an idea of how bad the injury is and whether it is healing.
• Look for muscle diseases such as Duchenne’s muscular dystrophy.
• Look for a disease your child was born with such as malignant hyperthermia.

How do I prepare my child for this test?

• If your child is being checked for muscle problems, don’t let your child exercise or play sports for 24 hours before the test.
• Your child may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your child’s healthcare provider knows about any medicines, herbs, or supplements that your child is taking. Ask your child’s provider before stopping any of your child’s regular medicines.
• Talk to your child’s healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. For young babies, the heel is pricked and a small amount of the blood is taken. For older children, a small amount of blood is taken from a vein in the arm with a needle. The blood is collected in tubes and sent to a lab.

Ask your child’s healthcare provider when and how you will get the result of your child’s test.

What does the test result mean?

Some of the reasons your child’s CK level may be higher than normal are:

• Your child has a muscle disease
• Your child has recently been in an accident or hurt a muscle
• Your child has exercised or played sports a lot
• Your child has recently had surgery
• Your child has a serious burn
• Your child had a recent seizure
• Your child has an infection

If your child’s CK level is high, the test may be repeated often to see if the level is decreasing

What if my child’s test result is not normal?

Test results are only one part of a larger picture that takes into account your child’s medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your child’s healthcare provider about the results and ask questions, such as:

• If your child needs more tests
• What kind of treatment your child might need
• What lifestyle, diet, or other changes your child might need to make