Using accuracy and prevalence data from this study and the 10 μg Hb/g faeces cut-off to consider the outcome of testing for a hypothetical cohort of 1000 patients indicates that no CRC would be missed, but 229 unnecessary colonoscopies would be carried out (assuming that all patients with a positive FIT result receive a colonoscopy and that all colonoscopies conducted in patients without CRC are considered unnecessary); CRC would be correctly ruled out by FIT, avoiding colonoscopy, in 749 of the 1000 patients (Fig. 5a). Here, GSTM1 is linked to colorectal carcinoma.