Your urine contains many chemicals. Sometimes these chemicals form solids, called crystals. A crystals in urine test looks at the amount, size, and type of crystals in your urine. It's normal to have a few small urine crystals. Larger crystals or specific types of crystals can become kidney stones. Kidney stones are hard, pebble-like substances that can get stuck in the kidneys. A stone can be as small as a grain of sand, as big as a pea, or even larger. While kidney stones rarely cause serious damage, they can be very painful.

Other names: urinalysis (crystals) microscopic urine analysis, microscopic examination of urine

A crystals in urine test is often part of a urinalysis, a test that measures different substances in your urine. A urinalysis may include a visual check of your urine sample, tests for certain chemicals, and an examination of urine cells under a microscope. A crystals in urine test is part of a microscopic exam of urine. It may be used to help diagnose kidney stones or a problem with your metabolism, the process of how your body uses food and energy.

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• Sharp pains in your abdomen, side, or groin
• Back pain
• Blood in your urine
• Frequent urge to urinate
• Pain when urinating
• Cloudy or bad-smelling urine
• Nausea and vomiting

You will need to provide a sample of your urine. During your office visit, you will receive a container to collect the urine and special instructions to make sure the sample is sterile. These instructions are often called the "clean catch method." The clean catch method includes the following steps:

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• Wash your hands.
• Clean your genital area with a cleansing pad. Men should wipe the tip of their penis. Women should open their labia and clean from front to back.
• Start to urinate into the toilet.
• Move the collection container under your urine stream.
• Collect at least an ounce or two of urine into the container, which should have markings to indicate the amount.
• Finish urinating into the toilet.
• Return the sample container as instructed by your health care provider.

Your health care provider may also request that you collect all urine during a 24-hour period. This is called a "24-hour urine sample test." It is used because the amounts of substances in urine, including crystals, can vary throughout the day. Your health care provider or a laboratory professional will give you a container to collect your urine and instructions on how to collect and store your samples. A 24-hour urine sample test usually includes the following steps:

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• Empty your bladder in the morning and flush that urine away. Record the time.
• For the next 24 hours, save all your urine passed in the container provided.
• Store your urine container in the refrigerator or a cooler with ice.
• Return the sample container to your health care provider's office or the laboratory as instructed.

Hinkle J, Cheever K. Brunner & Suddarth's Handbook of Laboratory and Diagnostic Tests. 2nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Urinalysis; 509 p.

Johns Hopkins Medicine [Internet]. Johns Hopkins Medicine; Health Library: Kidney Stones [cited 2017 Jul 1]; [about 3 screens].
Available from: http://www.hopkinsmedicine.org/healthlibrary/conditions/adult/kidney_and_urinary_system_disorders/kidney_stones_85,p01494

LaboratoryInfo.Com [Internet]. LaboratoryInfo.Com; c2017. Types of Crystals Found In Human Urine and Their Clinical Significance; 2015 Apr 12 [cited 2017 Jul 1]; [about 4 screens].
Available from: http://laboratoryinfo.com/types-of-crystals-in-urine

Lab Tests Online [Internet]. American Association for Clinical Chemistry; c2001–2017. Glossary: 24-Hour Urine Sample [cited 2017 Jul 1]; [about 3 screens].
Available from: https://labtestsonline.org/glossary/urine-24

Lab Tests Online [Internet]. American Association for Clinical Chemistry; c2001–2017. Urinalysis: The Test [updated 2016 May 26; cited 2017 Jul 1]; [about 4 screens].
Available from: https://labtestsonline.org/understanding/analytes/urinalysis/tab/test

Lab Tests Online [Internet]. American Association for Clinical Chemistry; c2001–2017. Urinalysis: The Test Sample [updated 2016 May 26; cited 2017 Jul 1]; [about 3 screens].
Available from: https://labtestsonline.org/understanding/analytes/urinalysis/tab/sample/

Lab Tests Online [Internet]. American Association for Clinical Chemistry; c2001–2017. Urinalysis: Three Types of Examinations [cited 2017 Jul 1]; [about 2 screens].
Available from: https://labtestsonline.org/understanding/analytes/urinalysis/ui-exams/start/2/

Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2017. Urinalysis: What you can expect; 2016 Oct 19 [cited 2017 Jul 1]; [about 6 screens].
Available from: http://www.mayoclinic.org/tests-procedures/urinalysis/details/what-you-can-expect/rec-20255393

Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co., Inc.; c2017. Urinalysis [cited 2017 Jul 1]; [about 2 screens].
Available from: https://www.merckmanuals.com/home/kidney-and-urinary-tract-disorders/diagnosis-of-kidney-and-urinary-tract-disorders/urinalysis

National Institute of Diabetes and Digestive and Kidney Diseases [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Definitions & Facts for Kidney Stones [updated 2017 May; cited 2017 Jul 1]; [about 4 screens].
Available from: https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones/definition-facts