 Urinalysis
Definition Alternative Names How the test is performed How to prepare for the test How the test will feel Why the test is performed Normal Values What abnormal results mean What the risks are Special considerations References DefinitionUrinalysis is the physical, chemical, and microscopic examination of urine. It involves a number of tests to detect and measure various compounds that pass through the urine. Alternative NamesUrine appearance and color; Routine urine test How the test is performedA urine sample is needed. Your health care provider will tell you what type of urine sample is needed. For information on how to collect a urine sample, see: The sample is sent to a lab, where it examined for the following: Physical color and appearance: - What does the urine look like to the naked eye?
- Is it clear or cloudy?
- Is it pale or dark yellow or another color?
The urine specific gravity test reveals how concentrated or dilute the urine is. Microscopic appearance: - The urine sample is examined under a microscope to look at cells, urine crystals, mucus, and other substances in the sample, and to identify any bacteria or other germs that might be present.
Chemical appearance: - A special stick ("dipstick") tests for various substances in the urine. The stick contains little pads of chemicals that change color when they come in contact with the substances of interest.
See also: Urine chemistry How to prepare for the testCertain medicines change the color of urine, but this is not a sign of disease. Your doctor may tell you to stop taking any medicines that can affect test results. Medicines that can change your urine color include: - Chloroquine
- Iron supplements
- Levodopa
- Nitrofurantoin
- Phenazopyridine
- Phenothiazines
- Phenytoin
- Riboflavin
- Triamterene
How the test will feelThe test involves only normal urination, and there is no discomfort. Why the test is performedA urinalysis may be done: Additional conditions under which the test may be performed: Normal ValuesNormal urine may vary in color from almost colorless to dark yellow. Some foods (like beets and blackberries) may turn the urine a red color. Usually, glucose, ketones, protein, and bilirubin are not detectable in urine. The following are not normally found in urine: - Hemoglobin
- Nitrites
- Red blood cells
- White blood cells
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results. What abnormal results meanFor specific results, see the individual test article: What the risks areThere are no risks. Special considerationsIf a home test is used, the person reading the results must be able to distinguish between different colors, since the results are interpreted using a color chart. ReferencesMcPherson RA, Ben-Ezra J, Zhao S. Basic examination of urine. In: McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: W.B. Saunders Company; 2006:chap 27. Physician ReferenceCurrent Procedural Terminology (CPT)81000 | 81001 | 81002 | 81003 | 81005 | 81007 | 81015 | 81020 | 81050 | 81099
Review Date: 2/1/2011
Reviewed By: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
|