Crystals in Urine Test

Why this test may be ordered

• To help diagnose or monitor kidney stones and other kidney diseases
• To help diagnose or monitor urinary tract infections (UTIs)
• To help diagnose or monitor certain problems with metabolism
• As part of a urinalysis to check your general health
• If you have symptoms of a kidney stone or UTI, such as sharp pains in your lower abdomen, side, groin, or back; blood in urine; frequent need to urinate; pain when urinating; cloudy or bad-smelling urine; nausea and vomiting; fever and chills

Preparation and collection

You don't need any special preparations. To make sure your test results are accurate, carefully follow all instructions for providing your urine sample.

You will need to give a urine sample. Your provider may ask you to collect your sample using the clean catch method or a 24-hour urine test. For clean catch: wash hands, clean genital area with a wipe, start urinating into the toilet, then collect at least an ounce or two of urine into the container without touching the inside. For 24-hour test: collect all urine over 24 hours in a special container and store it in a refrigerator or cooler with ice.

There is no known risk to having a crystals in urine test.

Understanding results

The test results will usually show if you have any crystals in your urine, the amount, and what they are made of. It's best to ask your provider to explain what your results mean, because different types of crystals are linked to different medical conditions, and your provider may need to order other tests to make a diagnosis.

• No crystals or only a few small crystals: This is normal and usually does not cause problems. Limitation: A few small crystals are normal, but the test does not rule out all conditions. Next step: No specific follow-up is needed unless you have symptoms. Talk to your provider if you have concerns.
• Large amounts of calcium oxalate or calcium phosphate crystals: These crystals are the most common cause of kidney stones. Limitation: Having crystals does not always mean you have a medical condition that needs treatment. Large amounts may also be caused by certain medicines, diet, or not drinking enough fluids. Next step: Your provider may need to order other tests to make a diagnosis and discuss ways to prevent kidney stones.
• Large amounts of uric acid or urate crystals: Large amounts may form when metabolic problems, such as gout and type 2 diabetes, make your urine too acidic. Limitation: Having crystals does not always mean you have a medical condition that needs treatment. Large amounts may also be caused by certain medicines, diet, or not drinking enough fluids. Next step: Your provider may need to order other tests to make a diagnosis and discuss ways to prevent kidney stones.
• Large amounts of struvite crystals: Repeated urinary tract infections may cause large amounts of struvite crystals. Limitation: Having crystals does not always mean you have a medical condition that needs treatment. Large amounts may also be caused by certain medicines, diet, or not drinking enough fluids. Next step: Your provider may need to order other tests to make a diagnosis and discuss ways to prevent kidney stones.

• Having crystals in your urine doesn't always mean that you have a medical condition that needs treatment.
• Large amounts of some types of crystals may be caused by certain medicines, diet (especially too much animal protein), or not drinking enough fluids.
• Your provider may need to order other tests to make a diagnosis.
• The test results depend on proper sample collection; germs from the skin can contaminate the sample if instructions are not followed.

What to do next

If you have questions about your test results and how you can prevent crystals in urine, talk with your provider.

• What type of crystals were found in my urine?
• How many crystals were found, and are they considered a large amount?
• Do I need any other tests to find out what is causing the crystals?
• What can I do to prevent kidney stones or other problems related to crystals in urine?
• Should I change my diet or fluid intake based on these results?

Evidence source

U.S. National Library of Medicine: Crystals in Urine Test