Oxalate (24 hr urine oxalate)

Kidney

Report in 48Hrs

At Home

Fasting Required

Details

Measures urinary oxalate.

₹2,738₹3,911

30% OFF

24-Hour Urine Oxalate Test - Comprehensive Information Guide

Why is it done?
- Test Purpose: Measures the amount of oxalate excreted in urine over a 24-hour period to assess metabolic function and kidney stone risk
- Primary Indications: Evaluation of recurrent or multiple kidney stones (particularly calcium oxalate stones), family history of kidney stones, inflammatory bowel disease, history of small bowel resection or bypass surgery, hyperparathyroidism, and idiopathic hypercalciuria
- Clinical Timing: Typically performed after passing a kidney stone, during metabolic evaluation for stone disease, after acute stone episode (waiting 4-6 weeks for accurate results), and as part of preventive screening in high-risk patients
- Additional Uses: Diagnosis of primary hyperoxaluria, monitoring patients on high-dose vitamin C supplementation, assessment of enteric hyperoxaluria, and evaluation of chronic kidney disease progression
Normal Range
- Normal Reference Ranges: Males: 4-45 mg/24 hours (average 20-25 mg/24 hours) Females: 4-40 mg/24 hours (average 15-20 mg/24 hours) Children: 0.5-4 mg/kg/24 hours SI Units: 44-497 µmol/24 hours (average 221-276 µmol/24 hours)
- Result Interpretation Categories: Low (<10 mg/24 hours): Below normal excretion Normal (10-45 mg/24 hours): Standard reference range Mildly Elevated (45-75 mg/24 hours): Borderline high risk Moderately Elevated (75-150 mg/24 hours): Increased stone formation risk Significantly Elevated (>150 mg/24 hours): Very high stone formation risk, suggests primary hyperoxaluria or significant secondary causes
- Units of Measurement: mg/24 hours (milligrams per 24 hours) or µmol/24 hours (micromoles per 24 hours). Conversion: 1 mg = 11.05 µmol
- Clinical Significance: Normal results indicate appropriate oxalate metabolism and excretion; elevated levels suggest increased risk for calcium oxalate stone formation. Values >45 mg/24 hours are considered hyperoxaluria and warrant investigation and intervention
Interpretation
- Low Oxalate Levels (<10 mg/24 hours): Suggests minimal kidney stone risk from oxalate; may indicate effective dietary restrictions or optimal metabolic function. Could reflect reduced dietary oxalate intake
- Normal Range (10-45 mg/24 hours): Normal oxalate excretion; low risk for stone formation from excessive oxalate. Typical metabolic pattern in healthy individuals with adequate kidney function
- Mildly Elevated (45-75 mg/24 hours): Mild hyperoxaluria indicating borderline increased stone risk; recommend dietary modifications, increased fluid intake, and dietary oxalate restriction; may require additional metabolic evaluation
- Moderately Elevated (75-150 mg/24 hours): Moderate hyperoxaluria indicating significantly increased stone formation risk; suggests secondary causes such as inflammatory bowel disease, enteric hyperoxaluria, vitamin B6 deficiency, or high dietary oxalate intake; warrants active intervention and investigation of underlying cause
- Significantly Elevated (>150 mg/24 hours): Severe hyperoxaluria indicating very high stone formation risk and potential kidney damage; raises concern for primary hyperoxaluria (genetic disorder) or severe secondary causes; requires immediate investigation, genetic testing consideration, and aggressive treatment with medications (allopurinol, potassium citrate) and dietary intervention
- Factors Affecting Results: Dietary oxalate intake (nuts, spinach, tea, chocolate), vitamin C intake (metabolized to oxalate), vitamin B6 status, hydration status, gastrointestinal absorption, kidney function, genetic factors, medications (topiramate, amphotericin B), systemic diseases (diabetes, chronic kidney disease), and recent stone passage (results artificially elevated)
- Clinical Significance Patterns: Single elevated result may reflect acute dietary change; persistent elevation suggests chronic metabolic disorder or pathological condition; serial measurements help distinguish transient from persistent hyperoxaluria; comparison with simultaneous calcium and citrate levels provides comprehensive stone risk assessment
Associated Organs
- Primary Organ Systems: Kidneys (primary target organ for stone formation and injury), Urinary tract (ureters, bladder susceptible to stone obstruction), Gastrointestinal tract (site of oxalate absorption), and Liver (involved in oxalate metabolism)
- Kidney Stone Disease: Hyperoxaluria is a major risk factor for calcium oxalate stone formation; elevated urinary oxalate increases supersaturation in urine, promoting stone crystallization and recurrent stone disease
- Primary Hyperoxaluria (Genetic Disorders): Type 1 (PH1): AGXT gene mutation causing massive oxalate overproduction (often >150 mg/24 hours), progressive kidney failure, systemic oxalate deposition; Type 2 (PH2): GRHPR gene mutation with moderate hyperoxaluria; Type 3 (PH3): HOGA1 gene mutation with milder phenotype
- Enteric Hyperoxaluria: Associated with small bowel resection, Crohn's disease, celiac disease, cystic fibrosis, and short bowel syndrome; decreased fat absorption leads to increased oxalate absorption in colon
- Idiopathic Hyperoxaluria: Elevated urinary oxalate without identified genetic mutation or secondary cause; may involve increased intestinal absorption or increased endogenous production
- Associated Medical Conditions: Vitamin B6 deficiency (cofactor for oxalate metabolism), Type 2 diabetes, chronic kidney disease, hyperparathyroidism, sarcoidosis, hyperthyroidism, obesity, and excessive vitamin C supplementation (>2000 mg/day)
- Potential Complications: Recurrent kidney stone formation, acute kidney injury from stone obstruction, chronic kidney disease progression, systemic oxalosis (in primary hyperoxaluria) with oxalate deposition in heart, bone, and eyes, chronic pain syndrome, urinary tract infections, sepsis from infected stones, and potential need for renal transplantation
Follow-up Tests
- Concurrent Stone Risk Assessment: 24-hour urine calcium, 24-hour urine citrate, 24-hour urine uric acid, 24-hour urine sodium, 24-hour urine creatinine, and 24-hour urine phosphate to establish complete stone risk profile
- Metabolic Evaluation Tests: Serum calcium, serum phosphate, serum magnesium, serum creatinine (kidney function), serum uric acid, fasting serum glucose, parathyroid hormone (PTH), vitamin B6 (pyridoxine), and vitamin D levels
- Primary Hyperoxaluria Testing: Plasma oxalate level (particularly if >150 mg/24 hours), glycolic acid (elevated in PH1), genetic testing for AGXT, GRHPR, and HOGA1 mutations, liver biopsy for enzyme analysis (in specialized centers), and plasma citrate
- Imaging Studies: Renal ultrasound to assess for stones and kidney structure, CT scan (non-contrast) for kidney stone characterization, 24-hour KUB X-ray for radiopaque stone monitoring in follow-up
- Secondary Cause Investigation: If hyperoxaluria identified: assess for inflammatory bowel disease (tissue transglutaminase IgA, endoscopy if indicated), evaluate intestinal fat absorption, assess dietary history and supplements, review medications causing hyperoxaluria
- Monitoring Frequency: Initial diagnosis: repeat 24-hour urine oxalate 6-12 weeks after dietary modifications to confirm normalization; after pharmacologic intervention: repeat at 4-6 weeks and annually; chronic stone formers on treatment: annual to biennial monitoring; primary hyperoxaluria: every 6-12 months or as clinically indicated
- Complementary Risk Assessment: Urine saturation studies (if available through specialty labs), stone risk calculation tools/nomograms using complete metabolic panel data, urine culture if history of infected stones, and assessment of citrate status (natural stone inhibitor)
Fasting Required?
- Fasting Status: NO - Fasting is NOT required for this test
- Special Collection Instructions: This is a timed 24-hour urine collection, not a blood test; patient should urinate normally but collect all urine (except the first morning void) for entire 24-hour period; discard first morning void, then collect all subsequent urine including next morning's first void to complete 24-hour cycle
- Patient Preparation Requirements: Maintain normal diet and hydration during collection (adequate fluid intake to achieve urine volume >1 liter/day); patient should drink normally (minimum 8-10 glasses of water daily) as hydration affects oxalate concentration; maintain usual physical activity level
- Medication Considerations: Continue all regular medications unless specifically instructed otherwise; do NOT discontinue medications; if on medications known to affect oxalate levels (topiramate, amphotericin B, excessive vitamin C supplements, vitamin B6, allopurinol), inform laboratory before collection; these medications should be noted but not stopped
- Dietary Restrictions: No special restrictions required for accurate results; maintain patient's normal diet (avoid sudden dietary changes during collection period as this artificially elevates oxalate); continue eating spinach, nuts, tea, chocolate, and other oxalate-containing foods normally consumed; avoid excessive vitamin C supplementation (>2000 mg/day)
- Collection Container Requirements: Use special collection container provided by laboratory; some laboratories provide container with preservative (such as hydrochloric acid or boric acid); check with your laboratory for specific container requirements; keep collection container at room temperature during 24-hour period (do NOT refrigerate unless specifically instructed)
- Timing Considerations: Ideally perform collection 4-6 weeks after a recent kidney stone event for more accurate baseline results; avoid collection during acute illness, fever, or significant dehydration as these affect oxalate levels; for repeated testing, attempt to collect at same time of year to account for seasonal dietary variations
- Additional Precautions: Ensure 24-hour collection is accurate (common source of error); label container with patient name, collection start/end times, and date; deliver specimen to laboratory promptly after collection completion; if specimen appears contaminated or incomplete, notify laboratory before submission

How our test process works!