A Faecal Immunochemical Test, commonly known as FIT, is a non-invasive screening method designed to identify hidden blood in stool samples. Its primary objective is to detect minute amounts of blood not visible to the naked eye. The test is convenient and performed in the privacy of one’s home.
Detecting Hidden Blood
The Faecal Immunochemical Test specifically identifies human haemoglobin, a protein found in red blood cells. This specificity means the test reacts only to human blood, distinguishing it from dietary sources. The presence of hidden human haemoglobin in stool can indicate bleeding in the lower gastrointestinal tract.
Bleeding in the lower digestive system can be a sign of various conditions, including colorectal polyps or early-stage colorectal cancer. These growths may bleed intermittently. Since the bleeding is often too small to be seen without a microscope, the FIT can detect these subtle indications. Identifying such bleeding at an early stage can lead to timely intervention and improved outcomes.
Performing the Test at Home
Performing a Faecal Immunochemical Test is a simple process completed at home. Individuals receive a collection kit from their healthcare provider, which contains a collection device, a sample tube, and instructions. Unlike older stool tests, FIT does not require specific dietary restrictions or medication changes, making preparation straightforward.
The collection process involves taking a small stool sample using the provided collection device, often a stick or brush. This sample is then placed into a specially designed tube containing a stabilizing solution. It is important to follow the kit’s instructions carefully to ensure an adequate and uncontaminated sample is collected. After sealing the tube securely, the sample is returned to a laboratory for analysis within a few days of collection.
Interpreting Your FIT Results
A “positive” Faecal Immunochemical Test result means human haemoglobin was detected in the stool sample. This indicates bleeding in the lower gastrointestinal tract, but it does not diagnose any specific condition. A positive result necessitates further investigation, such as a colonoscopy, to determine the exact cause of the bleeding. Follow-up tests identify whether the bleeding is due to benign conditions like haemorrhoids or more serious issues like polyps or cancer.
A “negative” FIT result signifies that no human haemoglobin was detected in the stool sample. While a negative result indicates a lower likelihood of certain conditions, it does not completely rule out the presence of polyps or cancer. Some growths may not bleed, or they may bleed intermittently, meaning a single negative test might miss them. Individuals should always discuss their FIT results with a healthcare provider to understand what the findings mean for their personal health and any recommended next steps for screening.
Why Choose FIT?
The Faecal Immunochemical Test offers several advantages as a screening method for colorectal conditions. Its non-invasive nature allows for convenient sample collection at home, which can increase participation rates in screening programs. The test also requires no dietary or medication restrictions, simplifying the preparation process for individuals. This ease of use makes it a practical option for regular screening.
Despite its benefits, the FIT does have certain limitations. It primarily detects bleeding and may not identify all polyps or cancers, especially those that do not bleed. A positive result requires subsequent, more invasive procedures like a colonoscopy to confirm the source of bleeding. Therefore, while FIT is a screening tool for detecting hidden blood, it is part of a broader strategy for monitoring colorectal health.