What is the magnesium test?

This test measures the amount of magnesium in your blood. Magnesium is a very important nutrient for your body. For example, your nerves, digestive system, and heart all need it to work well. You can get magnesium from food and supplements.

Why is this test done?

This test may help diagnose and treat a medical problem you are having. It does not diagnose a specific problem but it can help your healthcare provider know what other tests you might need. It’s also a way to see how well treatment for a disease is working.

How do I prepare for this test?

• You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Ask your provider before stopping any of your regular medicines.
• Talk to your healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. A small amount of blood is taken from a vein in your arm with a needle. The blood is collected in tubes and sent to a lab.

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

What does the test result mean?

Some of the reasons your magnesium level may be higher than normal are:

• You have kidney disease.
• You have a gland problem. For example, your thyroid gland may not be making enough thyroid hormone.

Some of the reasons your magnesium level may be lower than normal are:

• You are not getting the nutrients you need from your diet.
• You have frequent or long-lasting diarrhea.
• You drink too much alcohol.
• You have liver, pancreas, or kidney disease.
• You have too much calcium in your blood.
• You have severe burns.
• You have severe infections.
• You are taking certain medicines, such as digoxin, insulin, or a diuretic (water pill).

What if my test result is not normal?

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

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

If your magnesium level is low, your provider may recommend supplements to bring it back up.