Immune & Inflammation
IgA (Serum IgA)
Immune & Inflammation
Antibody protecting mucosal surfaces. Low levels linked to coeliac disease and infections.
VAT-exempt medical service
IgA is found where the body meets the outside world: the lining of the gut and airways, and in saliva and tears. It makes up roughly 10 to 15 per cent of the antibodies in blood. Selective IgA deficiency is the most common primary immune deficiency, affecting about one in six hundred people. Many have no symptoms at all, but it matters for one practical reason: the standard coeliac blood test is IgA-based and can be falsely negative in someone with IgA deficiency.
The test is used when a primary immune deficiency is suspected, particularly with recurrent infections of the sinuses, airways or gut, and alongside coeliac testing so that a negative result can be interpreted correctly. It is also used to follow known immune deficiency.
What a high value can mean
A raised IgA is seen with ongoing infection, chronic inflammation, liver disease, and in some autoimmune conditions. A markedly raised value can, rarely, indicate a blood disorder producing a single antibody type, and would then be investigated further.
What a low value can mean
A low IgA most often reflects selective IgA deficiency, which is usually harmless in itself but means the standard coeliac blood test cannot be relied upon: an alternative IgG-based test is used instead. Low IgA also occurs with certain medicines, including corticosteroids and immunosuppressants, and with conditions causing protein loss. If IgA is low alongside low IgG, a wider immune assessment is needed.
No special preparation is needed. Bring valid ID to your appointment.
Order your test
Choose your test and pay online. Your lab referral is created straight away.
Give your sample
Visit any of our partner sampling locations. No appointment needed at most of them.
The lab analyses it
Your sample is analysed at an accredited Swedish laboratory.
Get your results
Your values appear in your account with reference ranges and an explanation of each marker.
The usual coeliac test measures IgA antibodies against transglutaminase. If you have IgA deficiency you cannot produce those antibodies, so the test can be negative even with coeliac disease. That is why IgA is often measured at the same time.
Usually not. Most people with selective IgA deficiency have no symptoms and need no treatment. Some have more frequent airway or gut infections, and a minority develop autoimmune conditions, so it is worth knowing about.