The Immunoglobulin G4 (IgG4) test acts like a specialized detective for your immune system, identifying when one particular type of antibody has gone into overdrive and is causing problems throughout your body. Think of IgG4 as usually being the quiet member of your immune system's security team – normally present in small amounts but sometimes becoming overly aggressive and attacking your own organs. When IgG4 levels spike dramatically, it can lead to a condition called IgG4-related disease, where this rogue antibody creates chronic inflammation and scarring in organs like your pancreas, liver, kidneys, or salivary glands.
This test is especially valuable because IgG4-related disease is a master of disguise – it often mimics cancer or other serious conditions, leading to unnecessary worry and potentially inappropriate treatments. By measuring your IgG4 levels, doctors can distinguish between this treatable inflammatory condition and more serious diseases, giving you peace of mind and the right treatment path. The good news is that when caught early, IgG4-related disease typically responds well to treatment with medications that calm down your overactive immune system, but early detection is crucial since untreated inflammation can cause permanent organ damage over time.
Reviewed by Dr. Vu Tran Bloody Good’s Chief Medical Officer
You may benefit from the Immunoglobulin G4 (IgG4) Test
Essential for individuals with suspected IgG4-related disease, unexplained organ inflammation, autoimmune pancreatitis, or anyone needing evaluation of chronic inflammatory conditions.
Multiple food sensitivities
Chronic inflammation markers on blood tests
Chronic bloating after meals
How to prepare
No special preparation required. Inform healthcare provider of all medications, particularly immunosuppressive drugs or corticosteroids, as these may affect IgG4 levels and treatment monitoring.
Understanding results
Results show IgG4 levels compared to normal ranges. Elevated levels may suggest IgG4-related disease, but diagnosis requires correlation with clinical symptoms, imaging findings, and sometimes tissue biopsy results.
After the test
Address elevated IgG4 through comprehensive evaluation including imaging studies, possible tissue biopsy, and appropriate immunosuppressive treatment if IgG4-related disease is confirmed. Work with rheumatologists or specialists familiar with IgG4-related disease.
Frequently Asked Questions
IgG4-related disease is a systemic inflammatory condition characterized by elevated IgG4 levels, tissue infiltration, and fibrosis that can affect multiple organs including pancreas, bile ducts, salivary glands, and kidneys.
Elevated IgG4 may indicate IgG4-related disease, but diagnosis requires correlation with clinical symptoms, imaging findings, and sometimes tissue biopsy, as some healthy individuals may have elevated levels.
Treatment typically involves corticosteroids as first-line therapy, with other immunosuppressive medications used for maintenance or in cases of steroid resistance or intolerance.
Yes, IgG4 can be elevated in some allergic conditions, parasitic infections, and other inflammatory diseases, which is why comprehensive evaluation is needed for accurate diagnosis.
IgG4 levels typically decrease with effective treatment and may be monitored along with clinical symptoms and imaging studies to assess treatment response and detect disease relapse.
Commonly affected organs include pancreas (autoimmune pancreatitis), bile ducts, salivary glands, kidneys, lungs, lymph nodes, and retroperitoneal tissues, though virtually any organ can be involved.
You will be emailed a referral to take to your local collection centre. If you ever have any questions, we're here to help.
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