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Citric Acid 24 hr Urine

Order Code U003
Turnaround Time 24 hours
Test Includes


Specimen Requirements
Specimen Source
Transport Container
(Specimen Container)

Plastic screw-cap container

Preferred Specimens
10mL aliquot of a 24 hour urine
Minimum Volume (uL)
1.5 mL
Collection Instructions
(Transport Temperature)
Transport Refrigerated (cold packs)
Specimen Stability
Temperature Period
Room temperature 8 hours
Refrigerated 30 days
Frozen 60 days
Reject Criteria

Received room temperature; Acidified urine_x000D_

Special Instructions

Do not include first morning specimen; collect all subsequent voidings. The last sample collected should be the first morning specimen voided the following morning at the same time as the previous morning’s first voiding. Specify 24-hour total volume on container and test requisition.

Test Details
Spectrophotometry (SP)
Clinical Significance

Citric Acid, 24-Hour Urine without Creatinine – Citrate binds to calcium and inhibits kidney stone formation. Thus, low concentrations of citrate may lead to kidney stone formation. This is the most important risk factor for kidney stone formation in children. The treatment of calcium stones involves increasing urinary citrate excretion

Reference Ranges

100 – 1300 mg/24 h