The Visual Examination
During the visual examination of the urine, the laboratorian observes the urine's color, clarity, and concentration. 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, some medications, or the result of eating certain foods. For example, some people excrete red-colored urine after eating beets. The color is from the natural pigment of beets and is not a cause for worry. However, red-colored urine can also occur when blood is present in the urine and can be an indicator of disease or damage to some part of the urinary system.
Blood can also be a contaminant that gets into the urine unintentionally during collection, such as from hemorrhoids or from a woman's menstruation. Once this contaminating blood is in the urine, it will be detected during the chemical phase of a urinalysis, and the doctor will initially assume that 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 concentrated urine and the excretion of waste products in a smaller quantity of water, such as is seen with the first morning urine, with dehydration, and during a fever.
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 such as body lotions and powders. Other substances that can make urine cloudy, like red blood cells, white blood cells, or bacteria, indicate a condition that requires attention.