Urine Culture

About the Test

Purpose of the test

A urine culture test detects and identifies bacteria and yeasts in the urine, which may be causing a UTI.

Urine contains low levels of microbes, such as bacteria or yeasts, which move from the skin into the urinary tract and grow and multiply, causing a UTI.

Your doctor might order a urine culture if you have symptoms of a UTI, which can include a frequent urge to urinate, pain or burning during urination, cloudy or strong-smelling urine, or lower back pain.

Urine can be used to detect some sexually transmitted diseases (STDs). However, a urine culture is not the test of choice for STDs in adults. Some STDs such as chlamydia may be tested using a urine sample, but the testing method used detects chlamydia genetic material in the urine and is not a culture.

What does the test measure?

The urine culture is used, along with results from a urinalysis, to diagnose a UTI and identify the bacteria or yeasts causing the infection. If a urine culture is positive, susceptibility testing may be done to determine which antibiotics will inhibit the growth of the microbe causing the infection. The results will help your doctor determine which drugs are likely to be most effective in treating your infection.

When should I get this test?

A urine culture may be used to help diagnose infections of the kidneys or lower urinary tract. Typically, this test requires that the first urine voided in the morning be collected. The most common reason a urine culture is ordered is if you have symptoms of a UTI, including:

• A strong, frequent urge to urinate, even when you have just gone and there is little urine voided
• Pain and/or a burning sensation during urination
• Cloudy, strong-smelling urine
• Lower back pain

Additionally, a urine culture is used to screen pregnant women for asymptomatic bacteriuria, a condition in which significant amounts of bacteria are in the urine but do not cause symptoms. About 2% to 10% of pregnant women in the U.S. have this condition which can lead to a more serious kidney infection as well as an increased risk of preterm delivery and low birth weight.

Tell your doctor if you suspect an STD is causing symptoms so they can order the appropriate test. Urine cultures may be used to test for some STDs, but generally not for adults.