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Magnesium Test: About Your Child's Test

What is it?

This is a blood test that checks the level of magnesium in your child's blood. Magnesium is an important electrolyte. It's needed so that muscles, nerves, and enzymes work as they should. It also helps the body make and use energy.

Most of the magnesium in the body is found in the bones and inside the cells. Only a tiny amount is normally found in the blood.

Why is this test done?

This test is used to:

  • Find a cause for nerve and muscle problems, such as muscle twitches, muscle weakness, and irritability.
  • Check how well your child's kidneys are working.
  • Measure levels when magnesium is being given for treatment.

How do you prepare for the test?

In general, there's nothing you or your child has to do before this test, unless your doctor tells you to.

How is the test done?

A health professional uses a needle to take a blood sample, usually from the arm.

How long does the test take?

The test will take a few minutes.

Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if your child is having problems. Ask your doctor when you can expect to have your child's test results.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

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Care instructions adapted under license by your healthcare professional. If you have questions about a medical condition or this instruction, always ask your healthcare professional. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.