Urinalysis

The Visual Examination
During the visual examination of the urine, the laboratory scientist may look at the urine’s colour, clarity, and concentration. Urine can be a variety of colours, most often shades of yellow, from very pale or colourless to very dark or amber.

Unusual or abnormal urine colours can be the result of a disease process, some drugs or foods. For example, some people produce red-coloured urine after eating beetroot. The colour is from the natural pigment of beetroot and is not a cause for worry. Red-coloured 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 haemorrhoids or menstruation. Once this contaminating blood is in the urine, it will be detected during the chemical phase of a urinalysis, and your 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 colour is also a crude indicator of urine concentration:

Pale yellow or colourless urine indicates 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.

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