Doctors request a urine test to help diagnose and treat a range of conditions including kidney disorders, liver problems, diabetes and infections. Testing urine is also used to screen people for illicit drug use and to test if a woman is pregnant.
Urine can be tested for particular proteins, sugars, hormones or other chemicals, certain bacteria and its acidity or alkalinity.
Doctors can also tell a lot from how your urine looks and smells. For example dark urine could be a sign of dehydration; a cloudy appearance may suggest infection; if the urine is a reddish colour there may be blood in it; and a sweet smelling urine can be a sign of diabetes.
Do I have an infection?
The most common reason for analysing urine is to identify a bacterial infection in your urinary tract, your body’s drainage system for removing urine. Urinary tract infections are particularly common in women, affecting almost 50% in their lifetime.
Urine tests not only tell you if there’s an infection, they can identify the offending organism. That helps the doctor know how best to treat the infection, including prescribing the right type of antibiotic (one that particular microorganism is sensitive to).
At the GP, the first test uses a dipstick or strip test (sometimes called a rapid urine test). This involves dipping a specially treated plastic or paper strip into a urine sample collected in a sterile plastic pot.
The doctor compares the colour of the test strip with a chart of standard colours. If the strip test detects (is positive for) white blood cells (leucocytes), blood and/or chemicals called nitrites, infection is likely.
Then, the doctor sends off a sample of the urine to the laboratory for further testing. There, a laboratory technician can view it under a microscope to look for bacteria and cells. If the white cell count is above a baseline level, or if organisms are identified (and the patient has symptoms), an infection is very likely.