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A stool culture is a test on a stool sample to find germs (such as bacteria or a fungus) that can cause an infection. A sample of stool is added to a substance that promotes the growth of germs. If no germs grow, the culture is negative. If germs that can cause infection 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.
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.
A stool culture is done to:
Tell your doctor if you have recently taken antibiotics, travelled out of the country, or drunk untreated water. And let the doctor know if you had a recent test with contrast material, such as a barium swallow or a barium enema.
Stool samples can be collected at home. Or you may need to go to your doctor's office, a medical clinic, or 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 steps for each sample.
To collect the sample:
Take the sample to your doctor's office or the lab as soon as you can. You may need to take your sample to the lab within a certain time, usually within 30 minutes or less of collecting it. Tell your doctor if you think you may have trouble getting the sample to the lab on time.
Samples from babies and young children may be taken from diapers (if the stool does not have urine mixed with it). Or a narrow tube may be put into the baby's rectum while you hold the baby on your lap.
Sometimes a stool sample is collected using a rectal swab. The swab is inserted into the rectum, rotated gently, and then pulled out. It is placed in a clean, dry container and sent to the lab right away.
There is no pain from collecting a stool sample. If you are constipated, straining to pass stool may be painful.
If your doctor collects the stool sample using a cotton swab, you may feel some pressure or discomfort as the swab is inserted into your rectum.
Any stool sample may contain germs that can spread disease. Make sure to carefully wash your hands and use careful handling techniques to avoid spreading infection.
Stool culture test results usually take 2 to 3 days. But some cultures for fungus and parasites may take weeks to get results.
No disease-causing bacteria, fungi, parasites, or viruses are present or grow in the culture.
Bacteria (such as salmonella, shigella, or certain types of E. coli) grow in the culture. Fungi such as yeast are found in the stool.
If bacteria are found in the culture, sensitivity testing may be done to help choose the best treatment.
Your stool also may be looked at under a microscope to check for parasites such as Giardia.
Current as of: September 8, 2022
Author: Healthwise StaffMedical Review: Adam Husney MD - Family MedicineE. Gregory Thompson MD - Internal MedicineMartin J. Gabica MD - Family Medicine
Current as of: September 8, 2022
Author: Healthwise Staff
Medical Review:Adam Husney MD - Family Medicine & E. Gregory Thompson MD - Internal Medicine & Martin J. Gabica MD - Family Medicine
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