SERION reagents

Rheumatoid Factor Absorbent

SERION Immunologics Rheumatoid Factor (RF) Absorbent Bulk is recommended to remove RFs from serum and plasma samples prior to pathogen-specific IgM detection.
RFs are predominantly anti-IgG directed IgM class auto-antibodies which can be detected not only in patients with autoimmune diseases but also in serum of approximately 5 % of healthy individuals. These IgM RFs preferably bind to IgG immune complexes. Therefore, false-positive results may appear during pathogen-specific IgM detection. In samples with a high concentration of pathogen-specific IgG antibodies, weakly binding IgM antibodies may be displaced by stronger binding IgG antibodies. In such cases, IgM detection without RF absorption can lead to false-negative results. Therefore, it is recommended to pretreat serum samples with RF Absorbent before the detection of pathogen-specific IgM.

The RF Absorbent Bulk contains goat antibodies specifically directed against the Fc part of human IgG. Thus, the RF Absorbent precipitates human IgG together with potentially attached rheumatoid factors without cross-reactivity to other immunoglobulin isotypes. It is specified by a titer of minimum 15 mg/mL and can usually be diluted 3 to 4-fold to the final application concentration.


  • Removal of rheumatoid factors
  • Specific precipitation of human IgG
  • Avoidance of false-positive or false-negative IgM results
  • Continuous bulk availability


Rheumatoid Factor Absorbent Bulk
SERION reagents