It has also been proposed that the peroxidase reaction of ferric Hb(Fe3+) with hydrogen peroxide or lipid peroxides could accelerate Hb toxicity through the generation of free radicals and the accumulation of globin oxidation products.20, 38, 39, 40 In this study, covalent globin cross-linking products were identified in the urine of our canine hemoglobinuria model. Here, GSTM1 is linked to hemoglobinuria.