Chloride in Urine
Test Description
Chloride (Cl−) is the major anion of the extracellular fluid. Chloride levels have an
inverse relationship with those of bicarbonate; thus, they reflect acid-base status.
In individuals with too much base, urine chloride measurements help differentiate
the cause of the problem: loss of salt through dehydration, vomiting, or use of
diuretics (urinary chloride would be very low) or excess hormones such as cortisol
or aldosterone (urinary chloride would be very high).
Chloride has several functions, including maintaining electrical neutrality by
counterbalancing cations such as sodium (NaCl, HCl), acting as one component of
the buffering system, aiding in digestion, and helping to maintain osmotic pressure
and water balance. The amount of chloride excreted by the kidneys in a 24-hour
period is an indication of the patient’s electrolyte balance and mirror the dietary
intake of chloride and of sodium
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Normal Values 110–250 mEq/L (110–250 mmol/L SI units)
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Possible Meanings of Abnormal Values
Increased Decreased
Cushing’s syndrome Addison’s disease
Dehydration Congestive heart failure
Excessive salt intake Diarrhea
Salicylate intoxication Diaphoresis
Syndrome of inappropriate Emphysema
ADH secretion (SIADH) Low-sodium diet
Starvation Malabsorption
Nasogastric suctioning
Pyloric obstruction
Renal damage
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Contributing Factors to Abnormal Values
• Drugs which may increase urinary chloride levels: bromides, mercurial diuretics,
thiazide diuretics
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Interventions/Implications
Pretest
• Explain 24-hour urine collection procedure to the patient.
• Stress the importance of saving all urine in the 24-hour period. Instruct the patient to
avoid contaminating the urine with toilet paper or feces.
Procedure
• Obtain the proper container containing no preservative from the laboratory.
• Begin the testing period in the morning following the patient’s first voiding, which is
discarded.
• Timing of the 24-hour period begins at the time the first voiding is discarded.
• All urine for the next 24 hours is collected in the container, which is to be kept refrigerated
or on ice.
• If any urine is accidentally discarded during the 24-hour period, the test must be discontinued
and a new test begun.
• The ending time of the 24-hour collection period should be posted in the patient’s room.
• Gloves are to be worn whenever dealing with the specimen collection.
Posttest
• At the end of the 24-hour collection period, label and send the urine container to the laboratory
as soon as possible.
• Report abnormal findings to the primary care provider.
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Clinical Alerts
• If urine creatinine is ordered along with chloride, the urine should be kept refrigerated
during collection.
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