A chloride test measures the level of chloride
in your blood or urine. Chloride is one of the most important
electrolytes in the blood. It helps keep the amount of
fluid inside and outside of your cells in balance. It also helps maintain
proper blood volume, blood pressure, and
pH of your body fluids. Tests for sodium, potassium,
and bicarbonate are usually done at the same time as a blood test for
Most of the chloride in your body comes from the salt
(sodium chloride) you eat. Chloride is absorbed by your
intestines when you digest food. Extra chloride leaves
your body in your urine.
Sometimes a test for chloride can be done
on a sample of all your urine collected over a 24-hour period (called a 24-hour
urine sample) to find out how much chloride is leaving your body in your
Chloride can also be measured in skin sweat to test for
Why It Is Done
A test for chloride may be done
- Check your chloride level if you are having
symptoms such as muscle twitching or spasms, breathing problems, weakness, or
- Find out whether you have
adrenal gland problems.
- Help find the
cause for high blood pH. A condition called metabolic alkalosis can be caused
by a loss of acid from your body (for example, from a loss of electrolytes
through prolonged vomiting or diarrhea). You may also have metabolic alkalosis
if your body loses too much sodium or you eat too much baking soda (sodium
How To Prepare
You do not need to do anything before
you have this test.
Tell your doctor if you:
- Are taking any medicines.
allergic to any medicines.
- Have had
bleeding problems or take blood-thinners, such as aspirin or warfarin
- Are or might be pregnant.
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?).