Urinalysis

This test identifies and measures some of the by-products of normal and abnormal metabolism, cells, cell fragments, and bacteria in urine. Urine is produced by the kidneys, which filter wastes out of the blood, help regulate the amount of water in the body, and conserve proteins, electrolytes, and other compounds that the body can reuse. Anything that is not needed is excreted in the urine.

Several diseases can be diagnosed in their early stages by detecting abnormalities in the urine. Abnormally high levels of glucose, protein, bilirubin, red blood cells, white blood cells, crystals, and bacteria can indicate disease. They may be present because: 1) There are elevated concentrations in the blood which spill over into urine, 2) Kidney disease has made the kidneys less effective at filtering or, 3) An infection has put bacteria and white blood cells into the urine .

A complete urinalysis consists of three distinct testing phases:

Visual examination, which evaluates the urine's colour, clarity, and concentration;

Chemical examination, which tests chemically for a number of substances that provide valuable information about health and disease; and

Microscopic examination, which identifies and counts the type of cells, casts, crystals, and other components (bacteria, mucous ) that can be present in urine.

Today, a routine urinalysis consists of the visual and the chemical examinations. Your urine may be examined under a microscope if there is an abnormal finding in one of the first two phases listed above or if your doctor specifically requests it.

Urine for urinalysis can be collected at any time. The first morning sample is the most valuable because it is more concentrated and more likely to yield abnormal results. Because of the potential (particularly in women) to contaminate urine with bacteria and cells from the surrounding skin, it is important to first clean the genitalia. Men should wipe the tip of the penis; women should spread the labia of the vagina and clean from front to back. As you start to urinate, let some urine fall into the toilet, then collect a sample of urine in the container provided.

A sample will only be useful for urinalysis if taken to the doctor’s surgery or laboratory for processing within a short period of time. If it will be longer than an hour between collection and transport time, then the urine should be refrigerated.