GSTM1 and colorectal carcinoma: If the 10 μg Hb/g faeces cut-off were applied to the expanded target condition, for the hypothetical cohort of 1000 patients, the number of missed cases would increase from 2 to 42 (2 CRC and 40 HRA); using this cut-off, 137 unnecessary colonoscopies would be carried out and AN would be correctly ruled out in 749 of the 1000 patients (Fig. 4b).