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Urine Culture
A urine culture grows any bacteria in a urine sample to confirm a urinary tract infection and find which antibiotic will treat it.
Quick answer
Urine Culture: what it is and what the results mean
A urine culture is a laboratory test where a urine sample is placed on a growth medium to see whether bacteria multiply. If they do, further testing identifies the bacteria and which antibiotics work against them.
- Why it is done: It is used to confirm a urinary tract infection (UTI), particularly when infections are recurrent, complicated, in pregnancy, in children, or not responding to treatment, and to guide the choice of antibiotic.
- Understanding results: A significant growth of a single bacterium confirms a UTI and shows which antibiotics are effective (sensitivities).
What it is
A urine culture is a laboratory test where a urine sample is placed on a growth medium to see whether bacteria multiply. If they do, further testing identifies the bacteria and which antibiotics work against them.
Why it is done
It is used to confirm a urinary tract infection (UTI), particularly when infections are recurrent, complicated, in pregnancy, in children, or not responding to treatment, and to guide the choice of antibiotic.
What to expect
You provide a clean mid-stream urine sample (starting to pass urine, then catching some mid-flow) in a sterile pot. It is sent to the laboratory, and culture results usually take one to three days.
Understanding the results
A significant growth of a single bacterium confirms a UTI and shows which antibiotics are effective (sensitivities). A negative culture makes a bacterial UTI unlikely and prompts consideration of other causes of symptoms.
Good to know
Risks and limitations
It is a completely safe test. Results can be affected by contamination if the sample is not collected cleanly, and a course of antibiotics started before the sample can reduce bacterial growth.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Urine Culture: frequently asked questions
Why is a mid-stream sample important?
Collecting urine mid-flow reduces contamination from bacteria around the opening, giving a cleaner sample and a more accurate result about whether there is a genuine infection.
How long do urine culture results take?
Bacteria need time to grow, so results usually take one to three days. If treatment is needed sooner, a doctor may start antibiotics based on symptoms and a dipstick while awaiting the culture.
Related tests
Other other investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Association for Laboratory Medicine / relevant professional body
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