Citrate is a key intermediate in the tricarboxylic acid cycle. In urine it forms soluble complexes with cations such as Ca++, Mg++ and Fe++, thus inhibiting urinary crystallisation and stone formation. Low levels of urinary citrate excretion (<1.0 mmol/24 h) may be found in patients with distal renal tubular acidosis, malabsorption syndrome and urinary tract infection.
Monitoring therapy for renal stones
|Sample & container required||Random urine sample in universal container or 24 hour urine collection (acidified optional)|
|Sample volume||Random urine: 8 mL or 24 hour urine collection|
|Turnaround time||Up to 6 weeks|
May be done on the same sample as oxalate.