GSTM1 and colorectal carcinoma: Previous smaller diagnostic accuracy studies quoted a sensitivity for CRC of very close to 100% for FIT.20,21 Subsequently, it became clear that dependent on the cut-off chosen, FIT will miss between 7% and 15% of patients with CRC.22–24 The sensitivity and specificity of FIT for CRC in this study aligns with the smaller studies that recruited patients fulfilling NG12 criteria.16,25 The authors’ previous study determined the optimal cut-off value for FIT to be ≥12 μg Hb/g faeces.