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Sodium Test

What is a sodium test?

This test measures the amount of sodium in your child’s blood. Sodium is one of several chemicals in the blood called electrolytes. Electrolytes help control the amount of fluid in your child’s body and the way your child’s muscles, nerves, and organs work, including your child’s heart. Your child need the right balance of sodium and other electrolytes in your child’s body to stay healthy. The balance of electrolytes in your child’s body can be affected by food, medicines, drinking too much or too little water, or problems with your child’s lungs, kidneys and other organs.

Salt is often the main source of sodium in your child’s diet.

Why is this test done?

The sodium level is usually measured along with several other electrolytes to help diagnose certain diseases or conditions. The test can be helpful for checking problems with the kidneys, adrenal glands, digestive system, muscles, and nerves.

This test may also be done to see how well treatment for a disease or condition is working.

How do I prepare my child for this 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.
  • Your child’s healthcare provider will tell your child when to stop eating and drinking before the test. Food and drink before the test may affect the results.
  • 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 your child’s arm with a needle. The blood is collected in tubes and sent to a lab.

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

What does the test result mean?

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

  • Your child has a lot of salt in the diet.
  • Your child has not been drinking enough fluids and is dehydrated.
  • Your child’s thyroid level is low.
  • Your child has been breathing very fast (hyperventilating).
  • Your child has kidney disease.
  • Your child has a serious burn.

Some of the reasons your child’s sodium level may be lower than normal are:

  • Your child has had a lot of vomiting or diarrhea.
  • Your child is taking certain medicines, such as a diuretic (water pill).
  • Your child’s kidneys or adrenal glands are not working well.
  • Your child has been drinking a lot of water.
  • Your child has liver or heart disease.
  • Your child has been exercising a lot (for example, just run a marathon).

Some medicines can affect the test results, such as diuretics (water pills).

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
Developed by RelayHealth.
Pediatric Advisor 2015.2 published by RelayHealth.
Last modified: 2014-04-29
Last reviewed: 2014-04-29
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.
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