Chloride, 24-Hour Urine
Use
This test is used to evaluate the electrolyte composition of urine and for studies on acid-base balance. It helps to distinguish whether a case of metabolic alkalosis is chloride-responsive (salt responsive) or not. By measuring urine chloride levels, it assists in differential diagnosis of metabolic alkalosis, especially in scenarios of chloride depletion, which can often be corrected through chloride repletion. It is also used to identify cases of chloride-resistant conditions such as those caused by endogenous or exogenous corticosteroids, which may require further investigation for potential ACTH or aldosterone producing neoplasms.
Special Instructions
Ensure to state the total 24-hour urine volume on the test request form. Proper collection protocol must be followed to ensure accuracy of results.
Limitations
Halogens other than chloride, such as bromide present in urine, may falsely elevate the chloride results. Without concurrent urine sodium or potassium levels or corresponding serum electrolytes, the isolated urine chloride value might be misleading. The effect of profound potassium depletion on chloride reabsorption can complicate interpretation, and fetal urinary electrolytes are unreliable for assessing fetal renal function.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 2079-2
- 2078-4
- 2079-2
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
10 mL aliquot of entire collection
Minimum Volume
0.5 mL aliquot
Container
Plastic urine container, no preservative
Collection Instructions
For a 24-hour collection, instruct patient to void at 8 AM (or 8 PM), and discard the specimen. Then collect all the urine including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM [or 8 PM] the following day). Container must be labeled with patient's name and date and time collection started and finished.
Storage Instructions
Room temperature
Causes for Rejection
Improper labeling
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |