Table 1 shows the performance of FIT in patients with symptoms at a range of f-Hb thresholds that could be used to define a f-Hb that made a diagnosis of CRC very unlikely (i.e., the f-Hb that the GP could use to provide reassurance to the patient that significant GI disease was absent): note that the sixth column gives the number of CRC that were not initially referred in response to the f-Hb. The gene discussed is GSTM1; the disease is colorectal carcinoma.