What is Anti-Fodrin Ab, IgG (RDL)?
Anti-Fodrin Antibody, IgG is a blood test that looks for autoantibodies targeting a protein called fodrin, which is part of the structural framework (cytoskeleton) inside certain cells—especially those in salivary and tear glands. When the immune system mistakenly attacks fodrin, it can lead to glandular inflammation and dysfunction, contributing to autoimmune conditions.
This marker is often used to help diagnose Sjögren’s syndrome, a chronic autoimmune disorder that causes dry mouth, dry eyes, and sometimes systemic symptoms like joint pain and fatigue.
What does a positive result mean?
A positive Anti-Fodrin Ab, IgG test indicates the presence of immune activity against glandular tissues. This supports a possible diagnosis of:
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Sjögren’s syndrome, especially in early or “seronegative” cases
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Other autoimmune diseases like lupus or rheumatoid arthritis with gland involvement
This marker is especially useful when classic Sjögren’s antibodies like Anti-SSA (Ro) or Anti-SSB (La) are negative but symptoms still point toward autoimmune glandular disease.
What does a negative result mean?
A negative result means no detectable anti-fodrin IgG antibodies were found. This doesn’t completely rule out Sjögren’s or other autoimmune conditions—your doctor will consider your symptoms and may order further tests or imaging.
Next steps if elevated
If your result is positive:
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Your provider may refer you to a rheumatologist for further evaluation
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Additional tests (ANA, SSA/SSB, RF, CRP/ESR) may be ordered
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Management may include tear and saliva substitutes, immunomodulatory therapy, and regular monitoring for complications
Bottom Line
Anti-Fodrin Ab, IgG (RDL) is a valuable marker for detecting autoimmune activity affecting the body’s moisture-producing glands. It plays a key role in supporting the diagnosis of Sjögren’s syndrome, especially when other antibodies are negative but symptoms persist. Early detection can lead to better symptom control and monitoring for related autoimmune conditions.
Anti-Fodrin Ab, IgG (RDL)
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