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Urine culture is a laboratory test used to detect and identify bacteria or other microorganisms that may be causing a urinary tract infection. This test is performed by collecting a urine sample and placing it in a special growth medium that allows any present bacteria to multiply. The laboratory then examines the cultured sample to determine which specific organisms are present and in what quantities. Urine culture is one of the most common microbiological tests ordered by healthcare providers when a patient shows symptoms of a urinary tract infection.

The test is typically recommended when someone experiences symptoms such as frequent or painful urination, burning sensation while urinating, cloudy or foul-smelling urine, lower abdominal pain, or fever. It may also be ordered for people who have recurrent urinary tract infections, those who are pregnant, or patients who are about to undergo urinary tract procedures. For accurate results, proper urine collection is essential. The preferred method is a clean-catch midstream urine sample, which helps minimize contamination from bacteria normally present on the skin or genital area.

Results from a urine culture typically take between 24 to 48 hours, though some laboratories may provide preliminary results within 24 hours. A negative result means no significant bacterial growth was detected, suggesting no infection is present. A positive result indicates bacterial growth, and the laboratory report will specify the type of bacteria identified and the colony count, usually measured in colony-forming units per milliliter. A count of 100,000 or more colony-forming units per milliliter is generally considered significant for infection, though lower counts may be clinically relevant in certain situations.

Along with identifying the bacteria, the laboratory often performs antibiotic susceptibility testing, also known as sensitivity testing. This additional analysis determines which antibiotics will be most effective against the specific bacteria found in the urine sample. The results help healthcare providers select the most appropriate antibiotic treatment, which is particularly important given increasing concerns about antibiotic resistance. Understanding urine culture results enables better targeted treatment and helps reduce the unnecessary use of broad-spectrum antibiotics.