Chloride (Cl)
Test OverviewA 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
chloride. 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
urine. Chloride can also be measured in skin sweat to test for
cystic fibrosis. Why It Is DoneA test for chloride may be done
to: - Check your chloride level if you are having
symptoms such as muscle twitching or spasms, breathing problems, weakness, or
confusion.
- Find out whether you have
kidney or
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
bicarbonate).
How To PrepareYou do not need to do anything before
you have this test. Tell your doctor if you: - Are taking any medicines.
- Are
allergic to any medicines.
- 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?). How It Is DoneBlood testThe health professional taking a sample
of your blood will: - Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.
- Clean the needle site with
alcohol.
- Put the needle into the vein. More than one needle stick
may be needed.
- Attach a tube to the needle to fill it with
blood.
- Remove the band from your arm when enough blood is
collected.
- Put a gauze pad or cotton ball over the needle site as
the needle is removed.
- Put pressure on the site and then put on a
bandage.
Urine test- You start collecting your urine in the
morning. When you first get up, empty your bladder but do not save this urine.
Write down the time that you urinated to mark the beginning of your 24-hour
collection period.
- For the next 24 hours, collect all your urine.
Your doctor or lab will usually provide you with a large container that holds
about 1 gal (4 L). The
container has a small amount of preservative in it. Urinate into a small, clean
container and then pour the urine into the large container. Do not touch the
inside of the container with your fingers.
- Keep the large container
in the refrigerator for the 24 hours.
- Empty your bladder for the
final time at or just before the end of the 24-hour period. Add this urine to
the large container and record the time.
- Do not get toilet paper,
pubic hair, stool (feces), menstrual blood, or other foreign matter in the
urine sample.
The skin sweat test for chloride is primarily used to
test for cystic fibrosis. To learn more, see the topic
Sweat Test. How It FeelsBlood testThe blood sample is taken from a vein
in your arm. An elastic band is wrapped around your upper arm. It may feel
tight. You may feel nothing at all from the needle, or you may feel a quick
sting or pinch. Urine testThere is no pain while collecting a
24-hour urine sample. RisksBlood testThere is very little chance of a
problem from having a blood sample taken from a vein. - You may get a small bruise at the site. You
can lower the chance of bruising by keeping pressure on the site for several
minutes.
- In rare cases, the vein may become swollen after the blood
sample is taken. This problem is called phlebitis. A warm compress can be used
several times a day to treat this.
Urine testThere is no chance for problems while
collecting a 24-hour urine sample. ResultsA chloride test measures the level of
chloride in your blood or urine. Chloride is one of the most important
electrolytes in the blood, along with sodium,
potassium, and calcium. Chloride helps keep the amount of fluid inside and
outside of your cells in balance. NormalThe normal values listed here-called a reference range-are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab. Blood chloride levels are checked more often than urine chloride levels.
Results are usually available in 1 to 2 days. Chloride in urinefootnote 1| Adult: | 140-250
mEq per 24 hours (140-250
mmol per day) |
|---|
| Child (10-14 years): | 64-176 mEq/24 hours (64-176
mmol/day) |
|---|
| Child (younger than 6 years): | 15-40 mEq/24 hours (15-40
mmol/day) |
|---|
AbnormalHigh chloride levels may be caused
by: Low chloride levels may be caused by: - Conditions that cause too much water to build
up in the body, such as with syndrome of inappropriate antidiuretic hormone
secretion (SIADH).
- Addison's disease.
- A condition that raises the pH of the blood above the normal range (metabolic alkalosis).
- Heart failure.
- Ongoing vomiting.
What Affects the TestReasons you may not be able to
have the test or why the results may not be helpful include: What To Think About- The results from a blood or urine chloride test
do not provide enough information to diagnose a specific disease or problem.
Your doctor will talk with you about how your results may be caused by your
symptoms or past health.
- Potassium chloride (found in salt
substitutes) can lower your blood chloride levels but raise your urine chloride
levels.
- Tests for sodium, potassium, and bicarbonate usually are
done at the same time as a blood test for chloride.
- The skin sweat test for
chloride is used to test for
cystic fibrosis. To learn more, see the topic
Sweat Test.
ReferencesCitations- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Other Works Consulted- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
- Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
CreditsByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Adam Husney, MD - Family Medicine
Specialist Medical ReviewerMartin J. Gabica, MD - Family Medicine Current as ofApril 3, 2017 Current as of:
April 3, 2017 Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins. Last modified on: 8 September 2017
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