4027, 4027-5 – RF IgA

Highlights

• Use of rabbit IgG as coating antigen and polyclonal anti-human IgA for detection
• Quantitative determination of rheumatoid factor (RF) IgA in human serum
• Aids in the diagnosis of rheumatoid arthritis (RA) in conjunction with clinical and laboratory findings
• Detection of IgA RF, which is associated with extra-articular manifestations and disease severity
• High specificity and reproducibility based on well-characterized assay components
• Manual test for professional in vitro diagnostic use
• CE marked

Intended Use

The RF IgA is a quantitative immunoassay for the determination of rheumatoid factor (RF) IgA in human serum. The assay is intended to support the diagnosis of rheumatoid arthritis (RA) when used in conjunction with clinical evaluation, imaging techniques, and other laboratory findings. Quantification of RF IgA may provide additional information on disease activity and systemic involvement. The immunoassay is designed for manual professional in vitro diagnostic use.

Diagnostic Relevance

Rheumatoid arthritis (RA) is the most common chronic inflammatory joint disease, affecting approximately 0.5–1.0% of the population worldwide. The disease typically presents with painful, swollen joints, most often affecting the fingers and toes, but it can also involve larger joints such as the knees, shoulders, or hips. Symptoms often occur symmetrically and are usually most pronounced in the morning. As RA progresses, joint involvement increases and may lead to irreversible joint damage.

Laboratory diagnostics play a central role in the evaluation of RA. The serological determination of rheumatoid factors represents one of the most established diagnostic tools. Rheumatoid factors are autoantibodies that target the Fc portion of IgG and occur as IgM, IgG, or IgA isotypes. IgM RF appears most frequently, while IgA RF has gained increasing relevance because it correlates with disease severity and extra-articular manifestations.

Elevated concentrations of RF, particularly IgA RF, correlate with a more aggressive disease course and faster joint destruction. High RF levels are also commonly observed in patients with extra-articular manifestations such as rheumatoid nodules, vasculitis, polyneuropathy, or Sicca syndrome. Over time, RF IgA and IgG have emerged as prognostic markers for systemic involvement and progressive disease, supporting their use in patient stratification and long-term disease monitoring.