However, a limitation of our study is that group A had been referred to secondary care without use of the FAST score: thus, in this study, the use of the FAST score has actually been examined as a potential follow-up investigation prior to acceptance into colonoscopy, assessing whether the score, applied after referral on the grounds of clinical findings and f-Hb, would lead to a reduction in colonoscopies: it does, but a small number of patients with CRC and SBD would be missed, a less than ideal finding. Here, GSTM1 is linked to colorectal carcinoma.