Citric Acid (Citrate), 24-Hour Urine
Also known as: Citrate Excretion, Urine, Citrate, Urine
Use
The mean urinary citrate excretion rate in patients with idiopathic calcium urolithiasis has been found to be significantly lower than that of control groups. Hypocitraturia is common in patients with urolithiasis resulting from renal tubular acidosis and in patients with enteric hyperoxaluria. Citrate excretion is low in renal insufficiency.
Special Instructions
Record entire 24-hour total volume on the request form. pH must be 1 to 3 or the sample frozen without the addition of acid.
Limitations
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Other
Biomarkers
LOINC Codes
- 21203-5
- 6687-8
Result Turnaround Time
2-7 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
2 mL aliquot
Minimum Volume
1 mL aliquot
Container
Plastic Labcorp 24-hour urine container with 30 mL 6N HCl preservative (Labcorp No. 21584)
Collection Instructions
Collect 24-hour urine with 30 mL 6N HCl. Caution: Strong acid. Mix well. Instruct the patient to void at 8 a.m. and discard the specimen. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (i.e., 8 a.m. the next morning). Screw the lid on securely. Container must be labeled with patient's full name and date and time collection started and finished. Keep container refrigerated during collection. Preservative is not necessary during collection but should be added to urine collection within 24 hours. Final pH must be 1 to 3. Measure and record on the request form 24-hour total volume and send aliquot to the laboratory. Alternatively, the sample may be frozen without added acid.
Storage Instructions
Refrigerate at 2°C to 8°C after collection.
Causes for Rejection
Citrate: Boric Acid used as a preservative (Boric acid ≥1250 mg/dL may cause citrate results to be reduced by approximately 30%); multivitamin ≥397.5 mg/dL (estimated as 1 pill per day) may cause citrate results to be unmeasurable. Results of interference testing may not be representative of in-vivo characteristics of multivitamin consumption.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 29 days |
| Refrigerated | 29 days |
| Frozen | 49 days |