Abstract: Methods are disclosed for inactivating interfering binding proteins in a immunoassay for a member of a specific binding pair (sbp). The method comprises including in an assay medium containing a sample suspected of containing an sbp member and an interfering binding protein an effective amount of a water soluble compound having two substituted or unsubstituted phenyl groups linked to a common atom. When the sbp member or its sbp partner has two phenyl groups linked to a common atom, the compound has a number of groups other than hydrogen attached to the phenyl groups and the atom that differs by at least two from the number of such groups on the sbp member. When the sbp member or its sbp partner has two phenyl groups linked to a common atom and the binding protein is not an antibody, the compound has only one group other than hydrogen attached to a phenyl group or the common atom.

Abstract: A kit for inactivating interfering binding proteins in a immunoassay for a member of a specific binding pair (sbp). The method comprises including in an assay medium containing a sample suspected of containing an sbp member and an interfering binding protein an effective amount of a water soluble compound having two substituted or unsubstituted phenyl groups linked to a common atom. When the sbp member or its sbp partner has two phenyl groups linked to a common atom, the compound has a number of-groups other than hydrogen attached to the phenyl groups and the atom that differs by at least two from the number of such groups on the sbp member. When the sbp member or its sbp partner has two phenyl groups linked to a common atom and the binding protein is not an antibody, the compound has only one group other than hydrogen attached to a phenyl group or the common atom.

Abstract: Methods are disclosed for inactivating interfering binding proteins in a immunoassay for a member of a specific binding pair (sbp). The method comprises including in an assay medium containing a sample suspected of containing an sbp member and an interfering binding protein an effective amount of a water soluble compound having two substituted or unsubstituted phenyl groups linked to a common atom. When the sbp member or its sbp partner has two phenyl groups linked to a common atom, the compound has a number of groups other than hydrogen attached to the phenyl groups and the atom that differs by at least two from the number of such groups on the sbp member. When the sbp member or its sbp partner has two phenyl groups linked to a common atom and the binding protein is not an antibody, the compound has only one group other than hydrogen attached to a phenyl group or the common atom.

Abstract: Polyiodothyronine analog conjugates to glucose-6-phosphate dehydrogenase (G6PDH) are provided which find use in the determination of polyiodothyronine compounds, particularly thyroxine, normally in physiological fluids, such as serum. The G6PDH enzyme activity can be substantially reduced when bound to antibodies specific to polyiodothyronine as compared to the free or unbound polyiodothyronine analog enzyme conjugates. The polyiodothyronine analog is conjugated to the G6PDH by a linking group having a chain one atom in length.