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A urine culture is a test to find germs (such as bacteria) in the urine that can cause an infection. Urine in the bladder
is normally sterile. This means it does not contain any bacteria or other organisms (such
fungi). But bacteria can enter the
urethra and cause a urinary tract infection (UTI).
A sample of urine is added to a substance that promotes the growth of germs. If no germs grow, the culture is negative. If germs grow, the culture is
positive. The type of germ may be identified using a microscope or chemical tests. Sometimes other tests are done to find the right medicine for treating the infection. This is called sensitivity testing.
UTIs are more common in women and girls than in men. This may be partly
because the female urethra is shorter and closer to the
anus. This allows bacteria from the intestines to
come into contact more easily with the urethra. Men also have an antibacterial substance in their
prostate gland that lowers their risk.
A urine culture may be done to:
You do not need to do anything before
you have this test. If you are taking or have recently taken
antibiotics, tell your doctor.
need to collect a urine sample. Avoid urinating just before having this
Talk to your doctor if you have any concerns about the need for the test, its risks, how it will be done, or what the results will
mean. To help you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
You may be asked to collect a
clean-catch midstream urine sample for testing. The first urine of the day is
best because bacterial levels will be higher.
helps protect the urine sample from germs that are normally found on the penis
health professional may collect a urine sample by placing a
urinary catheter into the bladder. This method is
sometimes used to collect urine from a person in the hospital who is very ill
or who can't provide a clean-catch sample. Using a catheter to collect a urine
sample reduces the chance of getting bacteria from the skin or genital area in
the urine sample.
Collecting a urine sample from a small child or
baby may be done by using a special plastic bag with tape around its opening (a
U bag). The bag is attached around the child's genitals until he or she
urinates (usually within an hour). Then the bag is carefully removed. To
collect a urine sample from a very sick baby, a doctor may insert a needle
through the baby's belly directly into the bladder. (This is called a suprapubic
Collecting a urine sample is not painful.
Collecting a urine sample does not cause problems.
A urine culture is a test to find germs (such as bacteria) in the urine that can cause an infection. Urine culture results
are usually ready in 1 to 3 days. But some germs take longer to grow in the
culture. So results may not be available for several days.
No bacteria or other germs (such as
fungi) grow in the culture. The culture result is
Organisms (usually bacteria) grow in the
culture. The culture result is positive.
count of 100,000 or more bacteria per
milliliter (mL) of urine may be caused by an
infection. A count ranging from 100 to 100,000 could be caused either by
infection or by contamination of the sample. You may need to repeat the urine
culture. If the count is 100 or less, infection is unlikely. But you may have a count
of 100 or less if you are already taking
If test results are positive,
sensitivity testing may be done to help make decisions
You may not be able to have the test, or the results may not be helpful, if:
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
ByHealthwise StaffPrimary Medical ReviewerE. Gregory Thompson, MD - Internal MedicineAdam Husney, MD - Family MedicineSpecialist Medical ReviewerW. David Colby IV, MSc, MD, FRCPC - Infectious Disease
Current as ofJune 21, 2016
Current as of:
June 21, 2016
E. Gregory Thompson, MD - Internal Medicine & Adam Husney, MD - Family Medicine & W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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