GSTM1 and colorectal carcinoma: Moreover, predicting the risk for colorectal neoplasia using the conventional method that treats the disease status as the outcome and f-Hb as an independent variable with adjustment for relevant factors is not appropriate for the underlying factor (such as f-Hb) that is also a part of procedure related to the confirmation of disease as seen in our population-based screening for CRC with FIT that measures f-Hb.