Oxalate urine test

Your healthcare practitioner may request this test if you have frequent kidney stones. The test will help the doctor detect the cause of the kidney stone and recommend the appropriate treatment. 

Some common symptoms of kidney stones are:

• Cloudy or foul-smelling urine
• Severe pain in the lower back, sides and below the ribs
• Pain radiating to the lower abdomen and groin
• Pain on urination
• Pink, red or brown urine
• Frequent urination
• Fever and chills, in case of urinary infection
• Urinating in small quantities

An oxalate urine test is also done to check the effectiveness of a low oxalate diet - usually recommended to people who have kidney stones

Additionally, this test is done to check if a person is suffering from a rare inherited disorder called primary hyperoxaluria. In this condition, a person’s body starts to overproduce oxalates, making them prone to both kidney and bladder stones.

You do not require any special preparation for this test. Fasting is not needed either. If you are taking any prescribed, non-prescribed or illicit medications, inform your doctor before the test. Avoid foods such as spinach, chocolate, almonds and peanuts before the test. Foods rich in vitamin C should also be avoided before the test because these may affect your test results. If you are suffering from an inflammatory bowel disease or have undergone any intestinal or colon surgery, please inform your doctor before the test.

(Read more: Serum oxalate test)

A 24-hour sample is collected to check for urine oxalate levels. Your healthcare practitioner or nurse will explain the procedure to you before it is performed. You’ll be provided with a special container to collect the sample. For proper analysis, it is best that you start collecting the sample from early morning.

• Wash your hands thoroughly before taking the urine sample 
• Discard the first urine of the day. Note this time as the start of the collection process
• Save all the urine in the container for the next 24 hours. 
• Keep the urine container in a cool place. You can also refrigerate it until it is sent to the laboratory
• Label the sample before submitting it to the laboratory for testing

This is a simple test with no risks. It is advisable to stay at home while performing this test so that you can save and store the urine sample properly.

Normal results:

Normally about 45mg of oxalates are expelled through urine in 24 hours. A normal result indicates that you are not at risk of developing kidney stones.

Abnormal results:

Urine oxalate levels greater than 45 mg/24 hours are considered abnormal. High oxalate levels in the urine indicate that you have high chances of developing kidney stones. Other conditions associated with high oxalate levels are:

• Mild metabolic hyperoxaluria: This can be due to high intake of oxalate or vitamin C rich foods
• Enteric hyperoxaluria: Enteric hyperoxaluria can be due to inflammatory bowel disease, bowel resection, jejunoileal bypass or malabsorption. It is characterised by high oxalates in urine and low urine calcium
• Primary hyperoxaluria: This is an inherited rare disorder which causes overproduction of oxalate in the body
• Acute ethylene glycol poisoning

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.