Urine Culture

Definition of Urine Culture

A urine culture is a test done on a sample of urine. The urine is smeared on a special culture media in the lab and allowed to grow. It is then examined to see if there are infection-causing organisms present. If there are, the organisms are identified under a microscope.

Who is a candidate for the test?

A urine culture is ordered to see if a urinary tract infection is present.

How is the test performed?

There are two methods for collecting urine: the clean-catch method and the catheterization method.

Clean-catch method

In this method, the person is given special disposable wipes and a sterile container to hold urine.

• First, the person uses the wipes to clean around the urethra, the tube that passes urine out of the body.
• Next, the person urinates a small amount into the toilet and stops before the bladder is empty.
• The person collects a urine sample in the container provided.
• Finally, the individual finishes by urinating into the toilet.

Catheterization method

This method can be used when the person has difficulty urinating or is unable to cooperate.

• First, the area around the urethra is washed to prevent contamination.
• Next, the healthcare professionl passes a sterile, lubricated catheter through the urethra and into the bladder.
• Urine flows through the tube into the sterile container. The healthcare professional removes the catheter when the sample has been collected.

In the lab, the urine sample is grown on culture media. If any disease-causing microorganisms grow on the culture plate, these are identified. A sensitivity test may also be done to identify antibiotics that will kill the organisms. This allows the healthcare professional to choose a treatment program.

What is involved in preparation for the test?

An individual may be asked to drink several glasses of liquid to produce urine for the culture.

What do the test results mean?

Urine is normally sterile, so no microorganisms grow on the culture media. If microorganisms do grow, the test is generally positive. However, normal skin bacteria sometimes contaminate the urine specimen. The organism will be identified and treated as needed.