Citric acid, 24 hour urine-13495

Test info

Citric acid, 24 hour urine
Citrate excretion, urine
Citrate, urine
Citrate 24 hour urine

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.


Urine, 24 hr
10 mL aliquot of a 24 hour urine collection
2.5 mL aliquot of a 24 hour urine collection

Collect 24-hour urine with 30 mL 6N HCl

CAUTION: Strong acid

How to collect a 24 hr urine sample

Keep container refrigerated during collection.


  1. Measure and record the 24-hour total volume
  2. Mix well
  3. Transfer a 10 mL aliquot to a Transfer vial/tube with cap - 12mL (LabCorp) the laboratory.
    1. Alternatively, the sample may be frozen without added acid.
  1. Measure and record the 24-hour total volume
  2. Mix well
  3. Transfer a 10 mL aliquot to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp)
  4. Freeze within 24 hours of end of collection
  • Total volume

Refrigerated (preferred) - 14 days, if acidified

Ambient - 14 days, if acidified

Frozen - 14 days, no acidification required

Freeze/thaw cycles - stable x 3

  • Acetic acid used as a preservative
  • Boric acid used as a preservative


LabCorp Burlington (016865): R-LC
Mo - Fr
2 - 5 days

Spectrophotometry (kinetic at 340 nm)

Clinical and Interpretive info


320 - 1240 mg/24 hours


Result 21203-5