The FIT test is used to identify possible signs of bowel cancer. It determines this by detecting the quantity of human haemogolobin (blood) in stool samples with 88% sensitivity and 91% specificity for colorectal cancer. An increased quantity of haemoglobin in stool samples is present in individuals with diseases that involve haemorrhagic lesions in the gut such as intestinal tumours or their precursors. In such cases, individuals with a positive FIT result can be referred for further investigation usually through colonoscopy or CT colonoscopy.