FP3.3 - Sensitivity of Faecal Immunochemical Testing

Abstract Aim The use of faecal immunochemical testing (FIT) in the diagnosis of colorectal cancers (CRC) has become a routinely utilised and reliable investigation. In the symptomatic population, FIT may identify those patients who require urgent colorectal investigation. It is also commonly used as a triaging tool in bowel cancer screening. In this study we sought to assess the sensitivity of FIT in detecting CRC in our centre. Method Patients with histologically confirmed CRC were identified from a data set gathered from the hospital colorectal specialist services between January 2021 to January 2022. Thereafter, the hospital electronic systems were used to retrospectively gather the value of FIT tests for each CRC patient found. Results From 407 patients with CRC identified, only 256 patients who we successfully managed to obtain their pre diagnosis FIT result were included. From those, 235 patients were FIT positive and 21 patients had a false negative result. Therefore, this suggests a FIT sensitivity of 91.79%. Furthermore, we identified 14 patients who had a repeat FIT preformed. From which, one patient who was originally fit negative had a positive result on the repeat test. Conclusion While faecal immunochemical testing is highly sensitive and a useful screening tool, it's important to remember that it is not always accurate. Therefore if a patient has convincing history or symptoms, we should keep a high index of suspicion and investigate further. It also remains to be seen if the use of double FIT will help increase the sensitivity of detecting CRC.