Want more iVillage? Sign up for our
Newsletters
Sodium (Na) in Blood
About this test
A sodium test checks how much sodium (an electrolyte and a mineral) is in the blood. Sodium is both an electrolyte and mineral. It helps keep the water (the amount of fluid inside and outside the body's cells) and electrolyte balance of the body. Sodium is also important in how nerves and muscles work.
Most of
the sodium in the body (about 85%) is found in blood and
lymph fluid. Sodium levels in the body are partly
controlled by a
hormone called aldosterone, which is made by the
adrenal glands. Aldosterone levels tell the kidneys
when to hold sodium in the body instead of passing it in the urine. (See a
picture of the
adrenal glands 
or the
kidneys .) Small amounts of sodium are also lost
through the skin when you sweat.
Most foods have sodium naturally in them or as an ingredient in cooking. Sodium is found in table salt as sodium chloride or in baking soda as sodium bicarbonate. Many medicines and other products also have sodium in them, including laxatives, aspirin, mouthwash, and toothpaste.
Too much sodium in the diet may raise blood pressure in some people. For those who have high blood pressure, eating foods with a lot of sodium makes their chance of heart disease, stroke, and kidney damage higher. Heart failure gets worse when too much sodium is eaten. It increases the amount of water the body holds in and this causes swelling of the legs and hands. Some people have problems when they eat more than 4,000 milligrams (mg) of sodium per day.
Low sodium levels are uncommon and most often occur as a side effect of taking medicines that make you urinate more, such as diuretics. Severe diarrhea or vomiting or heavy sweating may also cause low sodium levels.
Other electrolytes, such as potassium, calcium, chloride, magnesium, and phosphate, may be checked in a blood sample at the same time as a blood test for sodium.
| By: | Healthwise Staff | Last Revised: September 1, 2010 |
| Medical Review: | E. Gregory Thompson, MD - Internal Medicine Avery L. Seifert, MD - Urology | |
© 1995-2011 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.
Welcome to Care Circle, an exclusive tool to help you take care of yourself and your loved ones. Here's how it works:
- Create profiles for yourself and your loved ones.
- Select the topics and conditions that interest each of you.
- Get customized news updates, original content, tools, and expert advice for each Care Circle member delivered directly to your personalized homepage.
The information you input is strictly private; you choose who has access to your Care Circle.
How do I add myself or someone else to my care circle?
Click on "Add someone." Fill out the short profile. Choose an avatar. Select the topics and conditions that interest this person from the pulldown menu. You can select as many as you want, but you must choose at least one. Click on "Add Someone" again. You should start getting updates immediately.
How do I save content to my Care Circle?
Click on "Manage My Care Circle." Select the tab of the person for whom you're saving content. Put your cursor over the piece of content that you want to save; a disk icon will appear in the righthand corner. Click on the disk and the piece of content will be moved to a save folder.
How do I add additional topics and conditions for someone in my Care Circle?
Click on "Manage My Care Circle." Select the tab for the person whose preferences you'd like to update. Under "Add More to Follow," select additional topics and conditions.
How do I delete topics and conditions for someone in my Care Circle?
Click on "Manage My Care Circle." Select the tab for the person whose preferences you'd like to update. Under "Follows," scroll over the topic or condition you want to delete. An "X" should appear on the righthand side. Click on the "X" and the topic or condition will be deleted from the list.
To manage your Care Circle, Please
Sign In.
