Table of Contents
Magnetic Resonance Imaging. Magnetic resonance imaging (MRI) techniques are showing promise for diagnosing urinary tract obstruction, but they do not yet accurately reveal small stones, or stones that do not cause a blockage. Because no radiation is involved with MRIs and ultrasounds, however, they are good options for children and pregnant women.
Urine Tests
Urine samples are needed to evaluate features of the urine, including its acidity and the presence of:
- Red or white blood cells
- Infection
- Crystals
- High or low levels of chemicals that inhibit or promote stone formation
Clean-Catch Urine Sample for Culturing. After determining that a kidney stone is present, the health care provider usually gives the patient a collection kit, including filters, to try to catch the stone or gravel as it passes out. The urine may also be tested (cultured) for the presence of infection-causing organisms. A clean-catch urine sample is almost always required for culturing. To provide a clean catch, do the following:
- First, wash your hands thoroughly, and then wash the penis or vulva and surrounding area four times with downward strokes, using a new soapy sponge each time.
- Begin urinating into the toilet and stop after an ounce or two.
- Position the container to catch the middle portion of the urine stream.
- Urinate the remainder into the toilet.
- Tighten the cap on the container securely, being careful not to touch the inside of the rim.
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Click the icon to see an image of a calcium urine test. |
Twenty-Four Hour Urine Collection. A 24-hour urine collection may be needed to measure urine volume and levels of acidity, calcium, sodium, uric acid, oxalate, citrate, and creatinine.
- You should not change any of your usual eating or drinking patterns when performing this test.
- Discard the first urination on the day of the test.
- Afterward, collect all urine passed over the next 24 hours, including the first urination on the morning of the second day.
- A second 24-hour urine collection may be needed to determine whether treatment is working, or it may be done if the first analysis was not conclusive and the doctor suspects a less common stone, such as a cystine or xanthine stone.
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Click the icon to see an image of a uric acid urine test. |
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Review Date: 06/08/2010
Reviewed By: Reviewed by: Harvey Simon, MD, Editor-in-Chief, Associate Professor
of Medicine, Harvard Medical School; Physician, Massachusetts
General Hospital. Also reviewed by David Zieve, MD, MHA, Medical
Director, A.D.A.M., Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
