Alternative laboratory determinates include; soluble transferrin receptor (sTfR) levels, sTfR/log ferritin ratio, percentage of hypochromic red blood cells, reticulocyte Hb content, hepcidin, and red cell indices may be helpful to identify absolute iron deficiency in patients with ferritin levels >100 μg/L, but these are mostly used in academic settings [15,16]. This evidence concerns the gene GSTM1 and Iron deficiency anemia.