If the 10 μg Hb/g faeces cut-off were applied to the expanded target condition, for the hypothetical cohort of 1000 patients, 22 cases of HRA would be missed, 205 unnecessary colonoscopies would be carried out and CRC and HRA would be correctly ruled out in 727 patients (Fig. 5b). This evidence concerns the gene GSTM1 and colorectal carcinoma.