Chloride, 24-Hour Urine
- Laboratory
- Labcorp
- Test code
- 003160
- Specimen
- Urine
- Fasting
- Not stated
- LOINC
- 2079-2
- Turnaround
- Within 1 day
Laboratory assay overview
Evaluate electrolyte composition of urine, acid-base balance studies. Distinguish whether or not a case of metabolic alkalosis is chloride-responsive (salt responsive). Sherman and Eisinger1,2 discuss bicarbonate excretion, blood volume, potassium depletion, and the differential diagnosis of metabolic alkalosis with loss of gastric juice (emesis, intubation) and after diuretics. Chloride depleted patients excrete urine with low chloride, <10 mmol/L. Such patients are chloride-responsive (ie, they respond to chloride sufficient to return body stores to normal). Metabolic alkalosis with low urine chloride is also found with villous tumors of the colon. Endogenous or exogenous corticosteroids produce urine chloride values >20 mmol/L. Such patients are chloride resistant. The finding of chloride resistant metabolic alkalosis may provide a stimulus to identify an ACTH or aldosterone producing neoplasm (eg, Cushing syndrome or Conn syndrome). In Bartter syndrome with metabolic alkalosis, there is usually increased urine chloride. The complex relationships of chronic pulmonary disease with metabolic alkalosis are mentioned by Sherman and Eisinger.
View complete laboratory reference notes
See table. Age Male mmol/24 hr Female mmol/24 hr 0-5 years Not established Not established 6-17 years 27-210 27-210 18-80 years 52-264 38-210 >80 years 29-181 4-148
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