What is a stool test?
A stool test may also be referred to as a “stool sample,” a “stool culture” or “fecal sample.” This type of test looks at fecal matter for evidence of a medical condition. The test may look for evidence of infection, allergy, blood or digestive problems.
Some stool tests are not cultures. Other stool tests are done to look for evidence of inflammation, bleeding or poor utilization of foods in the intestine. There are many different tests that look for many different conditions that may help explain your child’s illness. To learn what the results mean, it is important to speak with your child’s doctor.
What is a stool culture?
A stool culture may look for bacteria, viruses and other organisms in a patient’s stool. This test can help find out what’s causing a digestive tract infection. There are many types of stool tests for infection done at CHOC Children’s. Your child’s doctor will determine which type of test your child needs based upon his or her symptoms.
For this test, a stool sample is placed in a special container with the nutrients that bacteria or other organisms need to grow. The lab waits until enough organisms are present to be seen under a microscope. Once a doctor knows the type of organism causing an infection, he or she can diagnose and treat the illness.
What is the purpose of a stool culture?
Your child’s physician may request your child submit a stool sample to the lab if he or she thinks your child has a digestive tract infection. Symptoms may include:
- High fever
- Stools that contain blood or mucus
- Severe stomach pain or cramping
- Severe diarrhea
- Diarrhea that lasts more than a few days.
These symptoms are often caused by food poisoning, which is caused by eating food or drinking water that has been contaminated with bacteria, parasites, viruses, or other organisms.
A stool test may also be request if your child has:
- Immunity problems or if their white blood cell count is high. High white blood cell count is a sign that your child’s body is trying to fight off an infection.
- Traveled to a region where clean water is unavailable and has symptoms of parasitic infection. A stool test may also be requested if your child has diarrhea that doesn’t go away with treatment.
- Taken broad-spectrum antibiotics and is at risk for picking up a dangerous strain of bacteria, such as Clostridium difficile.
What do the test results mean?
Many things may affect your child’s lab test results, and even results that are different from the normal value may not mean there is a problem. To learn what the results mean, it is important to speak with your child’s doctor.
- Normal results are negative, meaning that no germs that usually cause illness were found in the stool culture and that your child doesn’t have an infection.
- Positive results mean that bacteria, parasites or other germs were found in your child’s stool culture and that they may be causing your child’s stomach problems.
- Sometimes the test shows a false-negative result, meaning that the test missed certain infectious bacteria. If your child still has symptoms of infection, your child’s doctor may order other tests to find out the cause of their stomach problems.
How is this test done?
This test requires a stool sample. Your child’s doctor will instruct you how to collect a sample into a disposable specimen container with a lid. Stool should not be collected from the toilet bowl or put toilet paper and then into the specimen container. It is important to wear rubber or latex gloves when collecting the sample and be sure to wash your hands thoroughly afterward. The laboratory may give you instructions on how to collect and submit the samples.
Does this test pose any risks?
This test poses no known risks.
What might affect my child’s test results?
Some tests may be affected by medications a child is taking or foods he or she may eat. It is important to tell the child’s doctor about all medicines, herbs, vitamins and supplements your child is taking and to follow any preparation instructions provided.