A stool culture is done to identify bacteria
or viruses that may be causing an infection. Although more than 50 different
kinds of bacteria normally live in the
intestines , large numbers of abnormal bacteria,
parasites can grow in the intestines and cause
infections and diseases.
For a stool culture, a stool sample is
collected in a clean container and placed under conditions that allow bacteria
or other organisms to grow. The type of infection is identified by noting the
appearance of the growth, by performing chemical tests on the stool sample, and
by looking at the sample under a microscope.
Depending on what
your stool is being tested for, you may only need to collect one stool sample,
or you may need several stool samples over a period of days.
Why It Is Done
A stool culture is done to:
- Find the cause of symptoms, such as severe or
bloody diarrhea, an increased amount of gas, nausea, vomiting, loss of
appetite, bloating, abdominal pain and cramping, and fever, especially if you drank untreated water from a stream or lake or have been traveling outside of the country.
and identify certain types of bacteria, viruses, or fungi that are
causing infections or diseases, such as
food poisoning, inflammation of the large intestine
- Identify a person who may not
have any symptoms of disease but who carries bacteria that can spread infection
to others. This person is called a carrier. A person who is a carrier and who
handles food is likely to infect others.
- Find out if treatment for
an infection has been effective.
How To Prepare
No special preparation is required
before having this test. Tell your doctor if you have recently taken
antibiotics, traveled out of the country, or
had a recent test with
contrast material, such as a barium swallow or a barium enema.
Talk to your doctor
about any concerns you have regarding 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?).
How It Is Done
Stool samples can be collected at home,
in your doctor's office, at a medical clinic, or at the hospital. If you
collect the samples at home, you may be given a special container.
You may need to collect more than one sample. Follow the same procedure
for each sample.
Collect the sample as follows:
- Urinate before collecting the stool so that you
do not get any urine in the stool sample. Do not urinate while passing the
- Put on gloves before handling your stool. Stool can contain
germs that spread infection.
Wash your hands after you remove your gloves.
- Pass stool (but no
urine) into a dry container. You may be given a plastic basin that can be
placed under the toilet seat to catch the stool.
- Either solid or liquid stool can be
- If you have diarrhea, a large plastic bag taped to the
toilet seat may make the collection process easier; the bag is then placed in a
- If you are constipated, you may be given a small
- Do not collect the sample from the toilet
- Do not mix toilet paper, water, or soap with the sample.
- Place the lid on the container and label it with
your name, your doctor's name, and the date the stool was collected. If you are
collecting more than one sample, use one container for each sample, and collect
a sample only once a day unless your doctor gives you other directions.