Solid-phase enzyme immunoassay of IgM-class rheumatoid factor: comparison of three methods for preparation of the solid-phase target IgG.

Three solid-phase forms of human IgG were compared for their ability to function as the binding target in an enzyme immunoassay for IgM-class rheumatoid factor (RF). IgG was either directly adsorbed to polystyrene beads (method A), or immunologically (method B) or covalently (method C) bound to protein adsorbed to beads. The data presented indicate that C is the method of choice for the preparation of the RF assay solid-phase IgG.