The Physical Examination

During the physical examination, the laboratorian observes the urine’s color and how clear it is (its clarity). Urine can be a variety of colors, most often shades of yellow, from very pale or colorless to very dark or amber.

Unusual or abnormal urine colors can be the result of a disease process or of eating certain foods. For example, some people excrete red-colored urine after eating beets. Under this circumstance, the reddish color of the urine, from the natural pigment of beets, is no cause for worry. However, red-colored urine can also occur when blood is present in the urine; if this is the case, seek medical attention.

Some substances that get into the urine during collection will affect urine color. In women, blood from hemorrhoids or menstrual blood can easily get into the urine sample unintentionally, contaminating it and causing it to look red. This is why it’s important to cleanse the genitalia and to follow the directions provided by health care providers for urine collection. Once this contaminating blood is in the urine, it will be detected during the chemical phase of a urinalysis, and your doctor will assume it came from the urinary tract. The importance of blood in urine is discussed further in the chemical and microscopic examination sections.

The depth of urine color is also a crude indicator of urine concentration:

• Pale yellow or colorless urine indicates a dilute urine where lots of water is being excreted.
• Dark yellow urine indicates the excretion of waste products in as little water as possible (for example, during a fever, or the first morning urine).

Accurate measurement of urine concentration can be done using a chemical test called specific gravity, that measures the amount of dissolved substances in the urine water.

Urine clarity refers to how clear the urine is. Usually laboratories report the clarity of the urine using one of the following terms: clear, slightly cloudy, cloudy, or turbid. “Normal” urine can be clear or cloudy. Substances that cause cloudiness but that are not considered unhealthy include mucus, sperm and prostatic fluid, cells from the skin, normal urine crystals, and contaminants (like body lotions and powders). Other substances that can make urine cloudy (such as red blood cells, white blood cells, or bacteria) indicate a condition that requires attention.

Urine color and clarity can indicate what substances may be present in urine. However, confirmation of suspected substances is obtained during the chemical and microscopic examinations.