Sodium (Na) in Urine
for sodium in the urine is a 24-hour test or a one-time (spot) test that checks
how much sodium is in the urine. Sodium is both an
electrolyte and a 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
Most of the sodium in the body (about 85%) is found in blood
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. 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
Low sodium levels
are uncommon and are most often caused by heart failure, malnutrition, and diarrhea.
Why It Is Done
A urine test to check sodium levels is
- Check the water and electrolyte balance of the
- Find the cause of symptoms from low or high levels of
- Check the progress of diseases of the kidneys or adrenal
How To Prepare
You do not need to do anything before
having this test.
Talk to your doctor about any
concerns you have regarding the need for the test, its risks, how it will be
done, or what the results will mean. To help you understand the importance of
this test, fill out the
medical test information form(What is a PDF document?).