Citric Acid (Citrate):Creatinine Ratio, Random Urine
Also known as: Citrate Excretion, Urine
Use
A timed 24-hour urine collection is the preferred specimen for measuring and interpreting this urinary analyte. Random collections normalized to urinary creatinine may be of some clinical use in patients who cannot collect a 24-hour specimen, typically small children. 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
pH must be 1 to 3 or the sample frozen without the addition of acid.
Limitations
Citrate results may be reduced by approximately 30% when Boric Acid is used as a preservative (Boric acid ≥1250 mg/dL). Multivitamin at ≥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.
Methodology
Other
Biomarkers
LOINC Codes
- 13722-4
- 2128-7
- 2161-8
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
2 mL
Minimum Volume
1 mL
Container
random urine transport tube or urine Monovette® with pH stabilizer (Labcorp No. 56015)
Collection Instructions
Collect urine and transfer to a random urine transport tube or urine Monovette® with pH stabilizer (Labcorp No. 56015). Alternatively, the sample may be frozen without added acid.
Storage Instructions
Refrigerate at 2°C to 8°C.
Causes for Rejection
Boric Acid used as a preservative; multivitamin ≥397.5 mg/dL may cause citrate results to be unmeasurable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 29 days |
| Refrigerated | 29 days |
| Frozen | 49 days |