Differed from that based on Hb-classified anemia and nonanemic, the levels of RET#, Rsf, MRV, and RHE showed remarkable differences between the two groups, and the anemic patients exhibited significantly decreased levels of the four indices, which further indicated that Hb concentration is a less sensitive index for the early diagnosis of overt nondigestive tract CRA. Here, GSTM1 is linked to anemia (phenotype).