This evidence was rather sparse and relied mainly on two small studies performed in Scotland, using different FIT analytical systems, and receiver operating characteristic analysis which gave the optimum balance between sensitivity and specificity for CRC, high-risk adenoma and inflammatory bowel disease as 10 μg Hb/g faeces.10 11 This was supported by a larger study in Spain.12 This evidence concerns the gene GSTM1 and colorectal carcinoma.