Removal method of rheumatoid factor interference in diagnostic measurement method

摘要

A method for treating biological samples, e.g., human sera or plasma, suspected of containing rheumatoid factors to eliminate cross-reactivity and false positive assay results in IgM immunoassays that are caused by the presence of rheumatoid factors in these biological samples. In one aspect, the method comprises diluting a biological sample with a sufficient amount of rheumatoid factor neutralization buffer to cause the pH of resulting reaction mixtures containing this sample and a solid phase material to be sufficiently low to cause rheumatoid factors in those mixtures to reduce their affinity to IgG antibodies to such an extent that they will not form a complex with IgG antibodies bound to the solid phase material, thereby facilitating the removal of these rheumatoid factors from the mixtures prior to the detection phase of a diagnostic assay. In another aspect of the invention, the method comprises introducing to a solid phase material containing a binding member-antibody complex a sufficient amount of rheumatoid factor neutralization buffer having a pH sufficiently low to cause rheumatoid factors bound to IgG antibodies bound to the solid phase material to reduce their affinity to the IgG antibodies to such an extent that the rheumatoid factors can be washed away from the solid phase material prior to the detection phase of a diagnostic assay.