RESUMO
We have characterized and identified uric acid as an interferent to peroxidase catalyzed reactions where hydrogen peroxide is generated at relatively low concentrations. The implications of these findings are important for those utilizing peroxidase as an indicator reaction where low primary substrate concentrations require their preliminary extraction or chemical modification. We have shown that the elimination of uric acid as an interferent from biologic fluid obviates the necessity for such treatment. In amniotic fluid, our data suggests that uric acid represents the only interference to peroxidase-catalyzed reactions, especially when using p-substituted phenols as proton donors. The removal of uric acid has been shown to eliminate hydrogen peroxide reduction and should allow for an increase in sensitivity and specificity for measurements incorporating a peroxidase-coupled indicator reaction, hence, more effective use of these reaction sequences. To our knowledge, this is the first report of a mechanism to eliminate hydrogen peroxide reduction in amniotic fluid.
