Oxidative interference in immunoturbidimetric assays for the quantification of immunoglobulins and complement proteins.

Immunoturbidimetric assays are widely used to quantify immunoglobulins and complement proteins but are susceptible to interference. This study evaluated the effects of oxidative agents, including the Fenton reaction and hypochlorous acid (HOCl), on these assays. Serum pools were oxidized in vitro, and IgA, IgG, IgM, C3, and C4 were measured. Oxidative conditions increased measured concentrations of IgA, IgM, C3, and C4, whereas IgG was unaffected by HOCl. Increased oxidative stress index values and reduced thiol levels confirmed oxidative modification, indicating potential impairment of assay accuracy under oxidative stress.