Test Quick Guide

Chloride is an electrolyte, a type of mineral that helps regulate the amount of fluid in the body and maintain the body’s acid-base balance. It is one of several important electrolytes, which include potassium, sodium, and bicarbonate.

A chloride test measures the amount of chloride in your blood or urine. Blood and urine chloride tests can help doctors determine if there is a problem with your lungs, kidneys, or other parts of the systems that control the balance of acids and bases in your body.

A chloride sweat test is used to diagnose cystic fibrosis, which causes digestive and breathing problems. This type of testing is covered on our Sweat Chloride Test page.

About the Test

Purpose of the test

The purpose of this test is to measure the amount of chloride in a sample of body fluid. Testing can determine if there are abnormalities in the body’s acid-base (pH) balance. A chloride test may be ordered for several reasons:

  • Diagnosis: This testing is used to find the cause of your symptoms. Chloride testing may be used to diagnose acid-base disorders, which are not diseases themselves. Instead, they signal the presence of an underlying health condition causing the body’s acid-base imbalance.
  • Monitoring: These tests are used to observe your condition over time. Chloride tests may be used to assess the effectiveness of treatments for acid-base disorders and their underlying cause.

What does the test measure?

Chloride testing measures the level of chloride in the blood or urine.

Chloride is an electrolyte present in body fluids. Electrolytes are minerals that hold an electrical charge. Their levels are closely linked to the body’s balance and body fluids’ pH, the level of a fluid’s acidity or alkalinity. This is also called acid-base balance.

The acid-base balance in the body is carefully controlled by the lungs, kidneys, and chemical processes that make up for small changes in the body’s pH. An acid-base disorder develops if the body cannot compensate for these changes in pH.

Measuring levels of electrolytes like chloride can reflect how well the body maintains a healthy acid-base balance.

When should I get this test?

A doctor may order chloride testing of the blood or urine if you are experiencing signs or symptoms caused by an acid-base disorder or a condition affecting the body’s balance of fluids.

Mild acid-base disorders may have few signs or symptoms. More severe acid-base disorders can cause a wide variety of symptoms. This is because an appropriate acid-base balance is fundamental to the function of the body’s major systems, including the cardiovascular, nervous, respiratory, and metabolic systems.

Finding a Chloride Test

How can I get a chloride test?

Chloride testing is typically performed at a doctor’s office. A blood or urine sample may be collected in the doctor’s office or a medical laboratory. In some cases, you will be sent home with containers for a 24-hour urine collection before returning your sample to the lab.

Can I take the test at home?

There is not currently an option for at-home chloride testing.

How much does the test cost?

The cost of a chloride test can vary based on many factors, including insurance coverage, whether it is part of a larger test panel, the facility collecting the sample, and the lab performing the analysis.

Testing is usually covered by insurance, but contacting your insurance company may be helpful because your expected costs are closely related to the details of your insurance plan.

Taking a Chloride Test

For chloride tests on blood, a sample is taken from a vein in the hand or arm in a medical setting such as a laboratory or a doctor’s office.

And for chloride tests on urine, you may be asked to collect a single urine sample in a bathroom at your doctor’s office, or you may be given supplies for at-home collection of all the urine you produce over a 24-hour period.

Before the test

Prior to a chloride test conducted on a sample of blood or urine, you may be asked to temporarily stop taking certain medications that can interfere with the test’s results. Check with your doctor for any specific pre-test instructions.

During the test

Chloride blood tests involve a phlebotomist or nurse collecting a blood sample. They will use a disinfectant wipe on a patch of skin on your elbow or hand. Then they will tie a strip of stretchy material around your arm above the cleaned area and insert a needle into a vein. There may be a sharp pain as the needle enters, but it passes quickly. The needle is attached to a collection tube, which will fill with blood. While the vial fills, the stretchy armband will be removed.

During a urine test, you will either need to provide a urine sample at the doctor’s office or you will need to do a 24-hour urine collection. If you provide urine at your doctor’s office, you will be given a small container and directed to the restroom.

A 24-hour urine collection involves saving all the urine your body produces in 24 hours. You will be sent home with one or more collection containers and directions on collecting the sample.

After the test

There should not be any side effects or restrictions on activity after getting a chloride test.

If you have a blood test, the health professional performing the blood draw will cover the spot where the needle was inserted with a band-aid and/or cotton ball.

Chloride Test Results

Receiving test results

Regardless of whether your chloride test is performed on a blood or urine sample, in most cases, you should receive your test results within a few business days.

Interpreting test results

When you receive your chloride test results, you will see a description of the chloride concentration in your blood or urine. Chloride levels in a test sample are typically measured in millimoles per liter (mmol/L) or milliequivalents per liter (mEq/L).

Test reports may also include reference ranges describing the expected chloride level in healthy patients. Reference ranges can vary depending on the laboratory processing your test, so it is best to look closely at your test report and contact your health care provider with any questions.

The following sections provide further information on the interpretation of different types of chloride tests.

Chloride blood test

In general, the reference range for chloride in a blood sample is 98 to 106 mEq/L, or mmol/L.

Having an elevated level of chloride in the blood is called hyperchloremia. This may be caused by a variety of health issues including:

  • Diarrhea
  • Metabolic acidosis, which involves too much acidity in the blood
  • Respiratory alkalosis, tied to excessive breathing and too much alkalinity in the blood
  • Renal tubular acidosis, a condition in which the kidneys aren’t able to remove enough acid from the blood
  • The use of certain medications

Having lower than expected levels of chloride in the blood is called hypochloremia. This may be caused by conditions such as:

  • Burns
  • Excess sweating
  • Vomiting
  • Congestive heart failure
  • Metabolic alkalosis, which involves too little acidity in the blood
  • Respiratory acidosis, in which breathing disruption causes excess acidity in the body

Chloride urine test

For a chloride urine test, there is significant variation in reference ranges based on your intake of chloride. Talk to your doctor to learn more about the reference ranges used to interpret your test.

Elevated levels of chloride in the urine can occur in several situations, including:

  • Problems with the adrenal glands
  • Kidney inflammation
  • Loss of potassium from the body
  • Polyuria, which is excessive urine production
  • Excess salt in the diet

Lower than expected levels of chloride in the urine may be due to:

  • Cushing’s syndrome, a condition in which the body produces too much of the hormone cortisol
  • Inadequate salt intake
  • Loss of fluids from diarrhea, vomiting, or sweating

When you get your test results, discuss them with your health care provider. Helpful questions could include:

  • What are my chloride test results?
  • What do these results mean for my health?
  • Do I need any follow-up tests?
  • Will I need to repeat this test? If so, when?

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