Urinalysis 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.
Urine appearance and color; Routine urine test
How the test is performed
A urine sample is needed. Your health care provider will tell you what type of urine sample is needed. Two common methods of collecting urine are 24-hour urine collection and clean catch urine specimen .
The sample is sent to a lab, where it is 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.
- 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 (urine chemistry ):
- 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.
How to prepare for the test
Certain medicines change the color of urine, but this is not a sign of disease. Your health care provider may tell you to stop taking any medicines that can affect test results.
Medicines that can change your urine color include:
- Iron supplements
How the test will feel
The test involves only normal urination, and there is no discomfort.
Why the test is performed
A urinalysis may be done:
- As part of a routine medical exam to screen for early signs of disease
- If you have signs of diabetes or kidney disease, or to monitor you if you are being treated for these conditions
- To check for blood in the urine
- To diagnose a urinary tract infection
Additional conditions under which the test may be performed:
Normal 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:
- Red blood cells
- White blood cells
Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.
What abnormal results mean
Abnormal results may mean you have an illness. Your health care provider will discuss the results with you.
What the risks are
There are no risks.
If a home test is used, the person reading the results must be able to tell the difference between different colors, since the results are interpreted using a color chart.
McPherson RA, Ben-Ezra J. Basic examination of urine. In: McPherson RA, Pincus MR, eds. . 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 28.