GSTM1 and colorectal carcinoma: We have previously reported on the transition from gFOBT to FIT at an f-Hb threshold of ≥80 μg Hb/g faeces in the SBoSP,9 and demonstrated an increased screen-detection rate for both CRC and adenomas, but at the cost of a lower positive predictive value for CRC and increased colonoscopy demand caused by a combination of increased uptake and higher test positivity.