What is the chloride blood test?

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

Salt is often the main source of chloride in your diet.

Why is this test done?

The chloride 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 for this test?

• You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Ask your provider before stopping any of your regular medicines.
• Talk to your healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. A small amount of blood is taken from a vein in your arm with a needle. The blood is collected in tubes and sent to a lab.

Ask your healthcare provider when and how you will get the result of your test.

What does the test result mean?

Some of the reasons your blood level of chloride may be higher than normal are:

• You have a lot of salt in your diet.
• You have not been drinking enough fluids to replace fluid you have lost through blood loss, sweat, or urine.
• Your body is making too much parathyroid hormone, which is a hormone that normally helps keep your electrolytes in balance.
• You have kidney disease.
• You are taking medicines that increase your chloride level.

Some of the reasons your blood level of chloride may be lower than normal are:

• You have been vomiting or have had diarrhea for a long time.
• You are taking medicines that lower your chloride level.

What if my test result is not normal?

Test results are only one part of a larger picture that takes into account your medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about the results and ask questions, such as:

• If you need more tests
• What kind of treatment you might need
• What lifestyle, diet, or other changes you might need to make