As evidenced by the results, there is a notable rise in the prevalence of CRC with increasing faecal haemoglobin level, with a positive predictive value (PPV) of 22.4 % at a cut-off of >200 μg Hb/g compared to 9.63% at >10 μg Hb/g. The gene discussed is GSTM1; the disease is colorectal carcinoma.