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Doctor's Assessment Included

Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.

Autoimmune

Immunoglobulin IgA: what the blood test measures

IgA testing evaluates mucosal immunity and validates coeliac screening results. For women, IgA deficiency is associated with higher rates of autoimmune conditions.

What It Measures

This test measures the serum concentration of immunoglobulin A. IgA is produced by plasma cells in mucosal tissues and protects body surfaces exposed to the external environment.

Why It Matters

IgA deficiency affects approximately 1 in 500 people and may be associated with recurrent respiratory and gastrointestinal infections. IgA levels must also be adequate for coeliac disease antibody tests (anti-TTG, endomysium) to be reliable.

When to Test

Testing could be indicated for recurrent sinopulmonary or gastrointestinal infections, suspected immunodeficiency, alongside coeliac disease testing (to validate IgA-based tests), or evaluation of IgA nephropathy.

Symptoms

Low Levels

Low IgA may be associated with recurrent infections (sinusitis, pneumonia, gastrointestinal), autoimmune conditions, and allergies. Many IgA-deficient individuals are asymptomatic.

High Levels

Elevated IgA may indicate chronic infections, IgA nephropathy, liver disease (particularly alcoholic), inflammatory bowel disease, or IgA myeloma.

Lifestyle Tips

If IgA deficiency is confirmed, discuss vaccination strategies and infection prevention with your healthcare provider. Wear a medical alert bracelet as IgA-deficient patients may have transfusion reactions to IgA-containing blood products.

Frequently Asked Questions

Why test IgA with coeliac disease screening?
Anti-TTG and endomysium tests are IgA-based. If you are IgA deficient, these tests may give false-negative results. IgG-based alternatives must be used instead.
Is IgA deficiency treatable?
There is no specific treatment to replace IgA. Management focuses on prompt treatment of infections and awareness of the condition.
Can IgA deficiency cause blood transfusion problems?
Yes. Some IgA-deficient patients develop anti-IgA antibodies, which can cause anaphylactic transfusion reactions. Washed or IgA-depleted blood products may be needed.