What It Is A stool (feces) sample can provide doctors with valuable information about what's going on when a child has a problem in the stomach, intestines, or other part of the gastrointestinal (GI) system. A stool culture helps the doctor see if there's a bacterial infection in the intestines. A technician places small stool samples in sterile plastic dishes with nutrients that encourage the growth of certain bacteria. The targeted bacteria will only grow if they're already in the stool sample. If bacterial colonies form, the technician evaluates them using a microscope and chemical tests to identify the organism. Why It's Done A doctor may request a stool culture to look for illness-causing bacteria such as: shigella salmonella yersinia campylobacter E. coli Sometimes, other bacteria are found. The stool culture might be ordered if your child has diarrhea for several days or has bloody diarrhea, especially if there's been an outbreak of foodborne illness in your community, your child has recently eaten undercooked meat or eggs or unpasteurized milk, or your child has recently traveled to certain places outside the United States. Preparation Unlike most other lab tests, a stool sample is usually collected by parents at home, not by health care professionals at a hospital or clinic. No special preparation is required, but tell your doctor if your child has recently taken antibiotics. Procedure The doctor or hospital laboratory will usually provide written instructions on how to collect a stool sample. If instructions aren't provided, here are tips for collecting a stool sample from your child: Be sure to wear protective gloves and wash your hands and your child's hands afterward. Many kids with diarrhea, especially young kids, can't always let a parent know in advance when a bowel movement is coming. So a hat-shaped plastic lid is used to collect the stool specimen. This catching device can be quickly placed over a toilet bowl, or under your child's bottom, to collect the sample. Using a catching device can prevent contamination of the stool by toilet water. Another way to collect a stool sample is to loosely place plastic wrap over the seat of the toilet. Then place the stool sample in a clean, sealable container before taking it to the lab. Plastic wrap can also be used to line the diaper of an infant or toddler who isn't yet using the toilet. The wrap should be placed so that urine runs into the diaper, not the wrap. Your child shouldn't urinate into the container. If possible, have your child empty his or her bladder before a bowel movement so the stool sample isn't diluted by urine. The stool should be placed into clean, dry plastic jars with screw-cap lids. Your child may be asked to provide a stool sample one or more times. For best results, the stool should be brought to the lab within a few hours. What to Expect When the sample arrives at the laboratory, a technician smears stool samples on a growth-encouraging substance inside sterile plates. These plates are each kept at a temperature that ensures the quickest growth of targeted bacteria. If no bacterial colonies form, the test is negative, meaning that there's no sign of a bacterial infection. But if bacterial colonies do form, the technician examines them under a microscope and may perform chemical tests to identify them more specifically. Getting the Results In general, the result of the stool culture is reported within 24 to 48 hours. Risks No risks are associated with collecting stool samples. Helping Your Child Collecting a stool sample is painless. Tell your child that collecting the stool won't hurt, but it has to be done carefully. A child who's old enough might be able to collect the sample alone to avoid embarrassment. Tell your child how to do this properly. If You Have Questions If you have questions about the stool culture, speak with your doctor. Back to Articles Related Articles Stool Tests Your child's doctor may order a stool collection test to check for blood, bacteria, ova, or parasites. Find out how this test is performed and when you can expect the results. Read More Stool Test: Giardia Antigen This test may be done if a child has watery diarrhea, abdominal pain, large amounts of intestinal gas, appetite loss, and nausea or vomiting. Read More Stool Test: H. Pylori Antigen A doctor may request an H. pylori antigen stool test if your child has symptoms that indicate a peptic ulcer, such as indigestion, abdominal pain, a full or bloated feeling, nausea, frequent belching, or vomiting. Read More Stool Test: Ova and Parasites (O&P) This exam may be done if your child has diarrhea for an extended period, blood or mucus in the stool, abdominal pain, nausea, headaches, or fever. Read More Stool Test: C. Difficile Toxin A doctor may request a C. difficile toxin stool test if your child has taken antibiotics in the past month or so and has had diarrhea for several days. Read More Stool Test: Fecal Blood Stool samples can provide information about a problem in the GI system. To test the stool for the presence of blood, a noninvasive test - the fecal occult blood test (FOBT) - is performed. Read More Yersiniosis Yersiniosis is an uncommon infection caused by the consumption of undercooked meat products, unpasteurized milk, or water contaminated by the bacteria. Read More Campylobacter Infections These bacterial infections can cause diarrhea, cramping, abdominal pain, and fever. Good hand-washing and food safety habits can help prevent them. Read More Shigella Infections (Shigellosis) Shigella are bacteria that can infect the digestive tract and cause a wide range of symptoms, from diarrhea, cramping, vomiting, and nausea, to more serious complications and illnesses. Read More Diarrhea Most kids battle diarrhea from time to time, so it's important to know what to do to relieve and even prevent it. Read More E. Coli Undercooked burgers and unwashed produce are among the foods that can harbor E. coli bacteria and lead to infection marked by severe diarrhea. Here's how to protect your family. Read More E. Coli Undercooked burgers and unwashed produce are among the foods that can harbor E. coli bacteria and lead to infection and severe diarrhea. Here's how to protect yourself. Read More Food Poisoning Did you ever eat something that made you feel ooky? It might have been food poisoning. Read More Salmonella Infections Salmonellosis is a foodborne illness caused by the bacteria salmonella. Symptoms include nausea, vomiting, abdominal cramps, diarrhea, fever, and headache. Read More Salmonellosis Salmonellosis is an illness caused by a bacteria found in raw food, soil, water and the bowel movements of some animals, including reptiles. Find out how to prevent this illness. Read More Salmonellosis People often think of salmonellosis as food poisoning, but food is only one way the bacteria Salmonella can be spread. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.