A stool sample is material passed during a bowel movement that is collected for laboratory testing. Analyzing the sample allows healthcare providers to check for various conditions, such as detecting signs of infection (bacteria, viruses, or parasites) or identifying abnormalities like occult (hidden) blood or markers of inflammation in the digestive tract. The accuracy of these diagnostic tests depends entirely on a carefully collected specimen.
Preparing for the Collection
Before collecting the sample, review the specific kit instructions provided by the ordering laboratory or physician, as requirements vary significantly based on the test being performed. Gathering equipment ensures a smooth process, typically including the sterile collection vial(s), a designated collection hat or plastic sheet, and disposable gloves. Some kits may contain a liquid preservative, which is often toxic and must be kept away from children and pets.
Certain medications and supplements can interfere with test results, requiring temporary cessation as directed by a healthcare provider. Non-essential medications like antacids, mineral oil, or bismuth-containing products may need to be avoided for several days. If a radiological procedure using contrast agents (e.g., a barium swallow) was recently performed, collection must be delayed until the compound has fully passed through the digestive system. Always pass urine before the bowel movement to prevent specimen contamination.
Step-by-Step Collection Methods
The physical collection process requires a specialized device to prevent the sample from contacting toilet water or urine. Contact with water or urine can destroy microorganisms and dilute the specimen, making it unsuitable for testing. For ambulatory patients, the most common method involves placing a “collection hat”—a plastic container designed to fit beneath the toilet seat—or a sheet of plastic wrap draped across the toilet bowl rim. The toilet seat is then lowered to secure the device in place.
Once collected, open the sterile container and use the small scoop or wand attached to the lid to transfer the sample. The required amount is usually small, often described as pea-sized or enough to reach a designated “fill line” if a preservative is present. If the stool is not uniform, collect small portions from several different areas, especially any part that appears bloody, slimy, or watery.
After transferring the correct amount, the lid must be screwed on tightly to prevent leakage. For infants or non-ambulatory patients, a clean, dry diaper can be lined with plastic wrap to collect the stool. The sample is then transferred from the plastic wrap into the sterile container.
Proper Storage and Submission
Immediately after sealing the container, clearly write all required identifying information on the label. This typically includes the patient’s full name, date of birth, and the precise date and time of collection. Laboratories will not process unlabeled or incorrectly labeled specimens. The filled specimen container is then placed into a leak-proof plastic biohazard bag, which is often provided in the kit.
Storage requirements depend highly on the type of test ordered, affecting the required temperature and submission speed. Fresh samples without a preservative generally need refrigeration and submission within 24 hours. Samples intended for certain parasite tests or those mixed with a chemical preservative may require storage at room temperature, as refrigeration could harm the organisms being tested for.
The healthcare provider will give specific instructions on where and how to deliver the sample, often requiring submission within a strict time limit (e.g., 24 or 48 hours). If the sample is mailed, it must be packaged securely according to the kit’s instructions, often including a specific cold pack or outer box to maintain the correct temperature during transport. Delivering the sample quickly maximizes the accuracy of the test results.