A crystals in urine test checks a sample of your urine (pee) for crystals. It shows what the crystals are made of, how large they are, and how many are in your urine.
Your urine contains many dissolved substances, including minerals. If you have too many minerals in your urine, certain minerals may clump together with other substances and form solid crystals.
It’s normal to have a few small crystals in your urine. But certain types of crystals may stick together and become kidney stones, which are hard, pebble-like pieces of material that form in the kidneys. Kidney stones can be as small as a grain of sand or as big as a pea or even larger. The acidity of your urine and can affect how stones form.
Small kidney stones may pass out of your body through your urine with little or no pain. A large kidney stone may get stuck and block your urine flow. This can cause pain or bleeding. But with treatment, kidney stones rarely cause serious damage.
Other names: urinalysis (crystals) microscopic urine analysis, microscopic examination of urine
What is it used for?
A crystals in urine test is often part of a urinalysis, a test that measures different substances in your urine. A urinalysis is used to check your general health, including the health of your urinary tract and kidneys. It may include a visual check of your urine sample, tests for certain chemicals, and an examination under a microscope to look for certain types of cells.
A crystals in urine test is part of a microscopic exam of urine. It may be used to help diagnose kidney stones. A crystals in urine test may also help diagnose a problem with your metabolism, the process of how your body uses food and energy. Problems with metabolism can affect both the amount of minerals in your urine and the amount of substances that prevent minerals from forming crystals.
Why do I need a crystals in urine test?
A urinalysis is often part of a routine checkup. Your health care provider may include a crystals in urine test in your urinalysis if you have symptoms of a kidney stone. These include:
- Sharp pains in your lower abdomen (belly), side, groin, or back
- Blood in your urine
- Frequent need to urinate
- Not being able to urinate at all or only urinating a little bit
- Pain when urinating
- Cloudy or bad-smelling urine
- Nausea and vomiting
- Fever and chills
What happens during a crystals in urine test?
You will need to give a urine sample for the test. This test may use the clean catch method or could be a 24-hour urine test.
A health care professional may give you a cleansing wipe, a small container, and instructions for how to use the “clean catch” method to collect your urine sample. It’s important to follow these instructions so that germs from your skin don’t get into the sample:
- Wash your hands with soap and water and dry them.
- Open the container without touching the inside.
- Clean your genital area with the cleansing wipe:
- For a penis, wipe the entire head (end) of the penis. If you have a foreskin, pull it back first.
- For a vagina, separate the labia (the folds of skin around the vagina) and wipe the inner sides from front to back.
- Urinate into the toilet for a few seconds and then stop the flow. Start urinating again, this time into the container. Don’t let the container touch your body.
- Collect at least an ounce or two of urine into the container. The container should have markings to show how much urine is needed.
- Finish urinating into the toilet.
- Put the cap on the container and return it as instructed.
24-hour Urine Test
Your provider may also request that you collect all your urine during a 24-hour period. This is called a “24-hour urine sample test.” It may provide more complete results because the amount of crystals and other substances in urine can vary throughout the day.
If you need to have a 24-hour urine sample test, you’ll be given a special container and instructions for how to collect and store your urine sample. Your provider will tell you what time to start. The test usually includes the following steps:
- To begin, urinate in the toilet as usual. Do not collect this urine. Write down the time you urinated.
- For the next 24 hours, collect all your urine in the container.
- Store the urine container in a refrigerator or in a cooler with ice.
- 24 hours after starting the test, try to urinate if you can. This is your last urine collection.
- Return the container with your urine to your provider’s office or the laboratory as instructed.
If you have hemorrhoids that bleed or are having your menstrual period, tell your provider before your test.
Will I need to do anything to prepare for the test?
You don’t need any special preparations for a crystals in urine test. To make sure your test results are accurate, be sure to carefully follow all the instructions for providing your urine sample.
Are there any risks to the test?
There is no known risk to having a crystals in urine test.
What do the results mean?
If your test results show that you have many crystals, large crystals, or certain types of crystals in your urine, it may be a sign that you have:
- One or more kidney stones
- Have a high risk of developing kidney stones
- A problem with your metabolism that affects the amount of minerals in your urine and/or the amount of substances that prevent crystals from forming
- A urinary tract infection (UTI)
- A genetic condition that causes kidney stones, such as cystinuria (uncommon)
Your provider may need to order other tests to make a diagnosis.
Having crystals in your urine doesn’t always mean that you have a medical condition that needs treatment. If you have a small kidney stone, it may pass through your urine on its own with little or no pain. Also, certain medicines, your diet, not drinking enough fluids, and other things can lead to crystals in urine. If you have questions about your test results, talk with your provider.
Is there anything else I need to know about a crystals in urine test?
Different minerals and other substances form different types of crystals in urine. A crystals in urine test can tell what type of crystals are in your urine. This information helps your provider understand why the crystals are forming and what would help reduce your risk for developing kidney stones in the future, such as:
- Drinking more water
- Making changes in your diet
- Taking or avoiding certain medicines