Fecal immunochemical test

Faecal Immunochemical Testing

Fecal Immunochemical Test (FIT), also known as the Immunochemical Fecal Occult Blood Test (iFOBT), is a medical diagnostic test used primarily as a screening tool for colorectal cancer. FIT works by detecting hidden blood in the stool, which can be an early sign of cancer or advanced polyps. Unlike the traditional Guaiac-based fecal occult blood test (gFOBT) that can react with any blood in the digestive system, FIT specifically targets human hemoglobin, making it more specific for bleeding from the lower digestive tract.

Overview

FIT is recommended for individuals at average risk of colorectal cancer, typically starting from the age of 50 to 75 years. The test is non-invasive and can be done at home with a kit provided by a healthcare provider. The process involves collecting a small sample of stool and sending it to a laboratory for analysis. If blood is detected, further diagnostic procedures, such as a colonoscopy, may be recommended to identify the source of bleeding.

Advantages

The main advantages of the Fecal Immunochemical Test include its specificity to human hemoglobin, which reduces the number of false-positive results from dietary sources. It is also more acceptable to patients due to the ease of sample collection and the lack of dietary or medication restrictions prior to the test. These factors contribute to higher screening rates and early detection of colorectal cancer and its precursors.

Limitations

While FIT is a valuable tool for screening, it does have limitations. It may not detect all cancers or large polyps, and a negative result does not guarantee the absence of colorectal cancer. Therefore, it is important for individuals to follow the screening schedule recommended by their healthcare provider and report any symptoms or changes in their health.

Comparison with Other Tests

Compared to the gFOBT, FIT has a higher sensitivity for detecting colorectal cancers and significant adenomas. However, it does not replace the need for a colonoscopy, which is still the gold standard for diagnosing colorectal cancer. The Colonoscopy allows for direct visualization of the colon and the removal of polyps during the procedure.

Implementation in Screening Programs

Many countries have implemented FIT as part of their national colorectal cancer screening programs due to its effectiveness and patient compliance. The frequency of testing varies, with annual or biennial screening being the most common recommendations.

Conclusion

The Fecal Immunochemical Test is an important tool in the early detection of colorectal cancer. Its ease of use, specificity, and non-invasive nature make it an effective option for widespread screening. However, it is part of a broader strategy that includes awareness, education, and access to follow-up diagnostic procedures to reduce the incidence and mortality of colorectal cancer.