GSTM1 and inflammatory bowel disease: Several studies from multiple countries have examined the faecal immunochemical test (FIT), which quantifies f-Hb concentration, and its ability to reliably exclude CRC, HRA and IBD in asymptomatic (i.e. screening) populations [9–12], and symptomatic ‘lower-’ [13–19] and ‘higher-’ risk [8, 20–28] patient groups.