Test Details
Methodology
Colorimetric; ion-selective electrode (ISE)
Result Turnaround Time
Within 1 day
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
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.
Special Instructions
State 24-hour volume on the test request form.
Limitations
Halogens other than chloride (bromide), which are also present in urine may erroneously elevate the chloride result. Isolated urine chloride, without urine sodium or potassium or without serum electrolytes, can provide misleading information. Discussion of electrolyte balance is beyond the scope of this manual (eg, effect of profound potassium depletion on impairment of chloride reabsorption). Fetal urinary electrolytes are an unreliable guide to evaluate fetal renal function.3
Custom Additional Information
Urine chloride is often ordered with sodium and potassium as a timed urine. The urinary anion gap [Na+ − (Cl− + HCO3−)] or [(Na+ + K+) − (Cl−)] is useful in the initial evaluation of hyperchloremic metabolic acidosis.4
Specimen Requirements
Specimen
Urine (24-hour)
Volume
10 mL aliquot of entire collection
Minimum Volume
0.5 mL aliquot (Note: This volume does not allow for repeat testing.)
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.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
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 |
Storage Instructions
Room temperature
Causes for Rejection
Improper labeling
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 003160 | Chloride, 24 hr Urine | 2079-2 | 013656 | Chloride, Urine | mmol/L | 2078-4 |
| 003160 | Chloride, 24 hr Urine | 2079-2 | 013284 | Chloride Urine | mmol/24 hr | 2079-2 |
| Order Code | 003160 | |||||
| Order Code Name | Chloride, 24 hr Urine | |||||
| Order Loinc | 2079-2 | |||||
| Result Code | 013656 | |||||
| Result Code Name | Chloride, Urine | |||||
| UofM | mmol/L | |||||
| Result LOINC | 2078-4 | |||||
| Order Code | 003160 | |||||
| Order Code Name | Chloride, 24 hr Urine | |||||
| Order Loinc | 2079-2 | |||||
| Result Code | 013284 | |||||
| Result Code Name | Chloride Urine | |||||
| UofM | mmol/24 hr | |||||
| Result LOINC | 2079-2 |