RESUMO
Comparison of the concentrations and activities of components in the oxidative-antioxidative system between blood plasma and serum. Blood plasma and serum samples were obtained from 38 healthy adults to evaluate malondialdehyde concentration, the total antioxidative capacity, superoxide dismutase activity, protein and non-protein sulphydryl groups, ascorbate, haemoglobin, methaemoglobin and protein. Blood plasma shows higher activity of superoxide dismutase, as well as higher concentrations of low-molecular sulphydryl groups and ascorbate, when compared to those in blood serum. The total plasma antioxidative capacity is also higher than that assessed in blood serum. Processes of blood coagulation and blood clot retraction lead to antioxidant consumption. The evaluation of oxidative-antioxidative system for diagnostic purposes should be performed in blood plasma.