A stool sample, or fecal matter, is analyzed in a laboratory to provide a snapshot of your gastrointestinal health. Doctors often order this non-invasive test to investigate symptoms like prolonged diarrhea, abdominal pain, or unexplained weight loss. The analysis can detect hidden blood (occult blood), which may signal conditions like polyps or colorectal cancer. It also identifies infectious agents such as bacteria, viruses, and parasites, and helps diagnose inflammatory conditions.
Necessary Supplies and Pre-Collection Preparation
Before collection, you must obtain the specific kit from your healthcare provider or the testing laboratory. This kit typically includes a sterile container, a scoop or applicator stick, and often a plastic collection device known as a “hat” or specialized sheet. Always confirm the exact instructions with the ordering lab, as preparation steps vary depending on the specific test.
Some tests, such as the Fecal Occult Blood Test (FOBT), require temporary dietary and medication adjustments to avoid false results. For three days prior to collection, avoid red meat, which can mimic blood in the test. High-dose vitamin C supplements should also be stopped as they can interfere with the chemical reaction and cause a false negative result.
Certain medications can also affect test accuracy, and you should consult your doctor about temporarily stopping them. Non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen are often restricted for up to seven days before collection, as they can cause minor gastrointestinal bleeding. Follow your provider’s specific instructions regarding any other restrictions.
Step-by-Step Collection Instructions
The collection process must keep the fecal matter pure, free from contamination by water or urine. Ensure your toilet bowl is clean and free of any chemical residue. Urinate before the bowel movement to eliminate any chance of urine mixing with the stool.
To prevent the sample from touching the toilet water, place the collection device securely on the rim beneath the toilet seat. If your kit does not include a special plastic hat, plastic wrap draped loosely across the bowl and secured by the toilet seat can serve the same purpose. The goal is to catch the stool so it remains dry.
Once the stool has been passed, open the sterile container and use the provided scoop or applicator stick to transfer the sample. Collect a small amount from at least two different areas of the stool mass, as pathogens or blood may not be uniformly distributed. For most tests, two to three small scoopfuls are sufficient, or enough to reach the fill line indicated on the vial.
After transferring the required amount, securely seal the container, ensuring the lid is tightened completely to prevent leakage. Dispose of the collection device and applicator stick according to the kit’s instructions. Immediately wash your hands thoroughly with soap and water.
Proper Handling, Storage, and Submission
Following collection, immediate handling and storage are important for preserving the viability of the organisms or chemical markers being tested. The container must be clearly labeled with your full legal name, date of birth, the date, and the exact time of collection. This information is necessary for the lab to correctly process and track your specimen.
The required storage temperature varies depending on the test ordered. Samples for bacterial culture or parasite examination often need to be kept refrigerated (39 to 46 degrees Fahrenheit). However, some specific tests, such as those for certain toxins, must be kept at room temperature and should never be refrigerated or frozen, as this can destroy the target substances.
The sample must reach the laboratory within a specific timeframe, often within 24 to 72 hours of collection. Delaying submission can lead to the death of living organisms, making the test results inaccurate. Always place the securely sealed and labeled container inside the provided biohazard bag for safe transport.
Troubleshooting Common Collection Issues
Contamination is the most common issue that can invalidate a stool sample, requiring the collection process to start over. The sample must not be mixed with urine, toilet water, or toilet paper, as these contaminants can dilute the specimen or introduce foreign substances. If the sample accidentally touches the water or is mixed with urine, discard it and attempt a new collection with the next bowel movement.
Another issue is collecting the sample while experiencing active bleeding, such as from hemorrhoids or during a menstrual cycle. Since many stool tests look for hidden blood, any visible or external blood will lead to a false positive result. Postpone collection until at least 48 to 72 hours after the bleeding has completely stopped.
If the collected amount is insufficient, do not attempt to combine it with a sample from a different bowel movement unless explicitly instructed by the lab. Different bowel movements represent different points in time and should not be mixed. If the sample is too small, wait for the next bowel movement and attempt a proper collection again with a new, sterile container if necessary.