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.

A 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:

• Clean catch urine specimen
• 24-hour urine collection

There are three basic steps to a complete urinalysis:

Physical color and appearance: What does the urine look like to the naked eye? For example, is it clear or cloudy? Pale or dark yellow or another color? The urine specific gravity test reveals concentrated or dilute the urine is.

Microscopic appearance: The urine sample is examined under a microscope. This is done to look at cells, urine crystals, mucous, and other substances, and to identify any bacteria or other microorganisms 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

Certain 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

The test involves only normal urination, and there is no discomfort.