Collecting a stool sample is a common procedure healthcare providers use to assess digestive health. These samples can help diagnose various conditions, including infections, inflammatory bowel diseases, malabsorption issues, and even screen for certain cancers. Proper collection and storage methods are crucial because incorrect handling can compromise the sample’s integrity, leading to inaccurate test results.
Immediate Handling After Collection
Many healthcare providers supply a specific collection kit, which often includes a hat-shaped device or plastic wrap to catch the stool without it touching the toilet water or urine. Contamination with water or urine can dilute the sample or introduce external bacteria, affecting test accuracy. Urinate before collecting the sample to avoid accidental contamination.
Once collected, transfer the stool into the provided sterile container using the kit’s spoon or spatula. Fill the container to the indicated level, typically one-third to halfway full, and securely seal the lid. Label the container clearly with your full name, the date, and the exact time of collection. Wash your hands thoroughly with soap and water after handling the sample.
Short-Term Storage Guidelines
Most unpreserved stool samples should be refrigerated at 2 to 8 degrees Celsius (approximately 35 to 46 degrees Fahrenheit). Refrigeration slows bacterial growth and analyte degradation, preserving the sample’s composition until testing. Place the sealed container in a clean, sealed plastic bag before refrigerating to prevent food contamination.
The maximum duration for refrigeration varies by test, but unpreserved samples are generally viable for 24 to 72 hours. For certain tests, like those for specific pathogens or molecular analyses, immediate lab delivery within a few hours may be necessary, or the sample might require a special preservative. Always consult the specific instructions from your healthcare provider or the laboratory, as specialized tests may have different temperature or time requirements.
Common Storage Mistakes to Avoid
Several common errors can compromise stool sample integrity, leading to unreliable results. Leaving the sample at room temperature for extended periods is a frequent mistake, as this allows bacteria to multiply rapidly and enzymes to degrade important components, altering the sample’s true composition. While some guidelines suggest up to 24 hours at room temperature, refrigeration is always preferable for preserving accuracy. Stool samples should ideally not remain at room temperature for more than two hours.
Another common pitfall is freezing the sample, unless explicitly instructed by the laboratory for a particular test. Freezing can damage cells and alter the structure of certain analytes, making them unsuitable for analysis. Using non-sterile or incorrect containers, or allowing the sample to mix with water, urine, or toilet paper, introduces contaminants that can invalidate the test. These contaminants can lead to false positive or false negative results, impacting diagnosis and treatment.
Transporting the Sample to the Lab
Transporting the collected and stored stool sample to the laboratory requires careful attention. Ensure the specimen container is tightly sealed to prevent leaks, then place it inside a sealed plastic bag, such as a zip-top bag. This double-containment method helps prevent contamination during transit and protects laboratory personnel. If your kit includes an outer pocket for the requisition form, place it there to keep it separate from the sample.
If the sample needs to remain cool during transport, especially for longer distances or in warm weather, use an insulated bag with an ice pack. This helps maintain the refrigerated temperature and preserves the sample’s integrity. Adhere to any specific delivery deadlines provided by your healthcare provider or the lab, as prompt delivery ensures the freshest possible sample for analysis. The sooner the sample reaches the lab, the more accurate the test results are likely to be.