RIDA® RF-Absorbens

Intended use:

For in vitro diagnostic use. RIDA® RF-Absorbens is used for the pre-absorption of IgG antibodies in human serum (or plasma) in selected serological RIDASCREEN® IgM ELISA tests.

Please also bear in mind the specific uses of RIDA® RF-Absorbens noted in the respective instructions for use for RIDASCREEN® IgM.

General information:

Compared to IgM antibodies, IgG antibodies predominate over the course of a long-term infection. For this reason, IgG antibodies can have a negative effect on IgM detection by blocking the specific binding sites. A test for IgM can have a false negative result.

Rheumatoid factors can, in contrast, have a false positive effect on IgM detection. Rheumatoid factors are usually antibodies of the IgM class (IgM-RF) directed against the constant region (Fc) of IgG antibodies. After IgG antibodies bind specifically to the test antigen, IgM-RF binds to its Fc region. Added anti-human IgM conjugate would then act like a positive IgM result by binding to the rheumatoid factors. For correct determination of IgM antibodies, absorption of
IgG antibodies is therefore recommended.

Test principle:
RIDA® RF-Absorbens forms immune complexes with human IgG antibodies. This prevents the antibodies from influencing the immunological test procedure.