Has your doctor recommended a urinary oxalate test?
If you suffer from recurrent kidney stones or urinary symptoms, your doctor may be looking for an underlying cause.The urinary oxalate test is an important diagnostic tool used to detect elevated levels of oxalate — a compound that can contribute to the formation of kidney stones.In this article from Dalili Medical, we’ll explain everything you need to know about this test:What is the urinary oxalate test? When is it ordered? How is it performed? And what do the results mean?

✅ What Is the Urinary Oxalate Test?

The urinary oxalate test is a diagnostic test used to measure the amount of oxalic acid (oxalate) in the urine.

Oxalate is a naturally occurring substance produced partly by the body and partly absorbed from certain foods. When oxalate levels become too high in the urine, it can bind with calcium to form calcium oxalate stones—the most common type of kidney stones.

 When Is the Urinary Oxalate Test Ordered?

Doctors typically request this test in the following situations:

• Suspected recurrent kidney stones

• Evaluating hyperoxaluria (excess oxalate in the urine)

• Monitoring dietary or medical treatment for kidney stones

• Investigating rare genetic conditions, such as primary hyperoxaluria

• In patients with symptoms like:

  • Flank or lower back pain

  • Blood in the urine (hematuria)

  • Urinary disturbances

  • Elevated creatinine or early signs of kidney dysfunction

 How Is the Test Performed?

• The most accurate method involves collecting urine over 24 hours to assess the exact amount of oxalate excreted.

• In some cases, a random urine sample may be used, though it is less accurate.

• Fasting is not required, but you may be advised to avoid certain foods before the test, including:

  • Spinach

  • Black tea

  • Chocolate

  • Nuts

  • Beets

 Normal Values for Urinary Oxalate

Reference ranges may vary by laboratory, but in general:

• Men: less than 40 mg/24 hours

• Women: less than 30 mg/24 hours

High oxalate levels in the urine are referred to as hyperoxaluria.

❗ What Do the Results Mean?

✅ Normal Levels:

• Your body is excreting oxalate at a normal rate.

• There's a low risk of kidney stone formation.

❗ Elevated Levels (Hyperoxaluria):

May indicate:

• Excessive intake of oxalate-rich foods

• Fat malabsorption (e.g., in chronic bowel diseases)

• A rare genetic disorder (primary hyperoxaluria)

• Dehydration or insufficient fluid intake

 Low Levels:

• Usually not a concern

• May result from dietary changes or oxalate-lowering medications

 What Is Hyperoxaluria?

Hyperoxaluria is a condition where the body excretes too much oxalate in the urine, increasing the risk of kidney stone formation. It is classified into three types:

1. Primary (genetic): Due to enzyme defects in the liver

2. Secondary: Caused by dietary factors or poor fat absorption

3. Related to fluid deficiency: Such as in severe dehydration

 What Happens After the Results?

If the oxalate level is high, your doctor may recommend:

• Reducing oxalate-rich foods in your diet

• Increasing fluid intake (2.5–3 liters per day)

• Taking calcium or vitamin B6 supplements in some cases

• Referral to a nephrologist or dietitian for further management

❓ Frequently Asked Questions About the Urinary Oxalate Test

Do I need to fast before the test?
No, but you may be advised to avoid certain foods that could affect the result.

How long does it take to get results?
Typically 1 to 3 business days.

Is the test painful?
❌ No. It’s a non-invasive urine test.

Is high oxalate always dangerous?
Not always, but persistent high levels can lead to kidney stones or even kidney damage if left untreated.

✍️ Summary

The urinary oxalate test is a key diagnostic tool for identifying the causes of recurrent kidney stones or metabolic disorders related to oxalate.
It is usually done through a 24-hour urine collection, and the results help guide treatment plans that may include dietary changes, increased water intake, and in some cases, medications.

If you experience frequent urinary symptoms or have a history of kidney stones, this test can be crucial in preventing complications and ensuring proper kidney function.