SOD concentration was measured by an indirect colorimetric method using the highly water-soluble tetrazolium salt WST-1, which produces a water-soluble formazan dye upon reduction with a superoxide anion. The Cayman Chemical SOD assay kit was used for the measurement of SOD activity in erythrocyte lysate. SOD activity was assessed by measuring the dismutation of superoxide radicals generated by xanthine oxidize and hypoxanthine in a convenient 96 well format. This technique included a quality-controlled SOD standard. The standard curve, which was generated using this enzyme, provides a means to accurately quantify the activity of all three types of SOD (Cu/Zn-, Mn-, and Fe-SOD). SOD concentration expressed in IU per gram of hemoglobin content. Results of SOD concentration, pH, pCO2, pO2, base deficit, Ht and Na concentration were recorded.