Chloride is a negatively charged molecule known as an electrolyte. It works with other electrolytes, such as potassium, salt (sodium), and carbon dioxide (CO2), to help keep the proper balance of body fluids and maintain the body's acid-base balance.

A test can be done to measure the amount of chloride in a urine sample.

See also:

• Chloride in diet
• Serum chloride (chloride blood test)
• Sweat chloride test
• Urine electrolytes test

A random urine sample or 24-hour urine collection may be needed.

If a 24-hour urine sample is needed:

• On day 1, urinate into the toilet when you get up in the morning.
• Afterwards, collect all urine in a special container for the next 24 hours.
• On day 2, urinate into the container when you get up in the morning.
• Cap the container. Keep it in the refrigerator or a cool place during the collection period.
• Label the container with your name, the date, the time of completion, and return it as instructed.

For an infant, thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on the infant. For males, place the entire penis in the bag and attach the adhesive to the skin. For females, place the bag over the labia. Diaper as usual over the secured bag.

This procedure may take a couple of attempts -- lively infants can move the bag, causing the urine to be absorbed by the diaper. Check the infant frequently and change the bag after the infant has urinated into it. Drain the urine from the bag into the container provided by your health care provider.

Deliver it to the laboratory or your health care provider as soon as possible upon completion.

The health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test.

Drugs that may decrease the level of chloride in the urine chloride include:

• Acetazolamide
• Nonsteroidal anti-inflammatory drugs

Drugs that may increase the level of chloride in the urine chloride include:

• Corticosteroids
• Loop diuretics
• Thiazide diuretics

The test involves only normal urination, and there is no discomfort.

Your doctor may order this test if you have signs of a disturbance in your body's fluid level or acid-base balance. It may be used to help determine the causes of hypokalemia, and to aid in the diagnosis of renal tubular acidosis.

The normal range is 20 to 250 milliequivalents per day (mEq/day). This range depends greatly on your salt intake and how hydrated you are.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Increased urine chloride levels may be caused by:

• Adrenocortical insufficiency
• Increased salt intake
• Inflammation of the kidney that results in salt loss
• Production of an unusually large amount of urine

Decreased urine chloride levels may be due to:

• Cushing syndrome
• Decreased salt intake
• Fluid loss that occurs with diarrhea, vomiting, sweating, and gastric suction
• Salt retention

There are no risks.

Fukagawa M, Kurokawa K, Papadakis MA. Fluid & electrolyte disorders. In: McPhee SJ, Papadakis MA, Tierney LM, Jr. Current Medical Diagnosis and Treatment 2007. New York, NY: McGraw Hill; 2007.