Chloride; urine

• On day 1, urinate into the toilet upon arising in the morning.
• Collect all subsequent urine (in a special container) for the next 24-hours.
• On day 2, urinate into the container in the morning upon arising.
• 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.

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 your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Place a diaper over the infant (bag and all). The infant should be checked frequently and the bag changed after the infant has urinated into the bag. For active infants, this procedure may take a couple of attempts--lively infants can displace the bag, causing an inability to obtain the specimen. The urine is drained into the container for transport to the laboratory.

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

How to Prepare:
No special preparation is necessary for this test, but if the collection is being taken from an infant, a couple of extra collection bags may be necessary.

How it Feels:
The test involves only normal urination, and there is no discomfort.

Risks:
There are no risks.

Why this Test is Performed:
Cl- is the major extracellular negative ion in the body. Its main purpose is to maintain electrical neutrality, mostly as a counter-ion to sodium. It often accompanies sodium losses and excesses. It also affects acid-base balance, that is, as CO2 increases, bicarbonate moves from the intracellular space to the extracellular space; to maintain electrical neutrality, more chloride tends to enter cells.

Normal Values:
The normal range is 110 to 250 mEq/day.

Note: mEq/day = milliequivalents per day

Abnormal Results:
Increased urine chloride excretion may be caused by:

• increased salt intake
• postmenstrual diuresis
• pharmacologic diuresis
• salt-losing nephritis
• adrenocortical insufficiency

Decreased urine chloride excretion may occur with:

• decreased salt intake
• adrenocortical hyperfunction
• PMS
• extrarenal fluid loss (such as diarrhea , vomiting , sweating , and gastric suction )
• salt retention

Cost:
The estimated cost is $25.

Special Considerations:
Interfering factors:
Drugs that may decrease urinary Cl- excretion include acetazolamide, ammonium chloride, androgens, chlorothiazide, cortisone, estrogen, guanethidine, hydrochlorothiazide, methyldopa, and NSAIDs.

Drugs that may increase urinary Cl- excretion include aldosterone ( aldosterone test), bicarbonates, corticosteroids, cortisone, hydrocortisone, loop diuretics, thiazide diuretics, and triamterene.