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Allergy & Intolerance

Total IgA: an antibody in saliva and breast milk, and what an IgA deficiency means

IgA is a kind of antibody, a protein of the immune system that according to the NVKC clears away foreign substances and fights infections, and according to the NVKC IgA is found mainly in saliva, breast milk, the stomach and the gut. Total IgA is the amount of this antibody that can be measured in the blood.

In a selective IgA deficiency, according to MSD, there is too little IgA in the blood while IgG and IgM are normal; according to MSD, most people do not notice it, but some get recurrent infections or autoimmune diseases. Only a blood test shows whether IgA is too low or too high.

Unilabs from age 16 and Certe from age 19 give 0.7 to 4 g/l as the reference values for total IgA.

Doctor's Assessment Included

IgA is an antibody, a protein that helps fight infections, found mainly in the stomach, the gut, saliva and breast milk. In the oldest age group of each of the four laboratories, the lower limit lies between 0.4 and 0.7 g/l and the upper limit between 3.5 and 4.0 g/l.

  • Total IgA is measured alongside the coeliac test anti-tTG IgA: with an IgA deficiency, that coeliac test can be falsely negative.
  • For children being tested for coeliac disease whose total IgA is low (low for their age, or below 0.2 g/l in children older than 3), the Dutch coeliac guideline advises a coeliac test based on IgG.
  • According to the NVKC, a slight rise in antibodies such as IgA is common during or just after an infection.

Total IgA: what Dutch laboratories use

There is no nationally agreed reference value; this is what individual laboratories publish.

The upper limit runs from 3.5 g/l at Star-shl to 4 g/l at Unilabs.

Reference ranges by group, in g/l
Star-shl · Everyone · 18 years and older 0.4–3.5 g/l
0.4 3.5
Unilabs · Everyone · 16 years and older 0.7–4.0 g/l
0.7 4
Certe · Everyone · 19 years and older 0.7–4.0 g/L
0.7 4
Diagnostiek voor U · Everyone · 16 years and older 0.4–3.5 g/L
0.4 3.5
0 4.4 g/l

Source: Star-shl

Source: Unilabs

Source: Certe

Source: Diagnostiek voor U

Each value as the laboratory itself publishes it, retrieved in 2026.

Total IgA: what this test measures

The total IgA test measures the amount of IgA in the serum in grams per litre (g/l), and according to the NVKC the reference values depend on age. At Certe, the lower limit is 0.4 g/l from 14 to 19 years and 0.7 g/l from 19 years.

Total IgA: why this value matters

According to MSD, a selective IgA deficiency causes no symptoms in most people, but others get recurrent infections of the sinuses and lungs, diarrhoea, allergies such as asthma, or autoimmune diseases such as coeliac disease, inflammatory bowel disease or systemic lupus erythematosus.

Total IgA: how the blood test works

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The draw
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Where
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Total IgA: when is testing worthwhile?

According to the NVKC, a doctor can have total IgA measured together with IgG and IgM when infections occur often or keep coming back, and the NVKC recommends having total IgA determined alongside anti-tTG IgA when screening for coeliac disease. According to MSD, a selective IgA deficiency is also suspected after an anaphylactic reaction, a severe allergic reaction, to a blood transfusion, with medicines that can cause an IgA deficiency, and in a family in which IgA deficiency, CVID (common variable immunodeficiency, another immune disorder) or autoimmune diseases occur.

Total IgA: symptoms of a high or low value

Low Levels

According to MedlinePlus, a low total IgA can come from a hereditary IgA deficiency, a gut disease with protein loss or multiple myeloma, a type of bone marrow cancer, and very rarely from agammaglobulinemia, a disorder with very low levels of antibodies. According to MSD, it is a selective IgA deficiency when IgA is below 7 mg/dl, equal to 70 mg/l, while IgG and IgM are normal.

High Levels

Like the other antibodies, total IgA can be slightly raised during or shortly after an infection, and according to the NVKC such a slight rise in antibodies is common. As possible causes of a raised total IgA, MedlinePlus names chronic infections, especially of the stomach and gut, inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, and multiple myeloma, a type of bone marrow cancer.

Total IgA: causes of a low or high value

What lowers the value

  • IgA deficiency without symptoms

    According to the NVKC, about 1 in 700 people has an IgA deficiency without symptoms.

  • Some medicines

    Medicines such as phenytoin and sulfasalazine can cause an IgA deficiency in some users.

  • Protein loss through the gut

    A gut disease that leads to protein loss can lower IgA.

What raises the value

  • Chronic infections, especially of the gut

    Chronic infections, especially of the stomach and gut, can raise IgA.

  • Inflammatory bowel disease

    Crohn's disease and ulcerative colitis can raise IgA.

  • Alcohol-related liver disease

    In a study of people with alcohol-related liver disease, IgA was raised in about 70 percent.

  • Multiple myeloma

    IgA can also be raised in multiple myeloma, a form of bone marrow cancer.

Total IgA: lifestyle and this value

Talk to your GP about an abnormal total IgA result. According to MSD, bacterial infections of the ears, sinuses, lungs, gastrointestinal tract or urinary and genital tract are treated with antibiotics as needed in a selective IgA deficiency. According to MSD, people with a selective IgA deficiency are advised to wear medical identification, so that they are not given plasma or immunoglobulins by accident.

Total IgA: frequently asked questions

How common is a selective IgA deficiency?

According to MSD, a selective IgA deficiency occurs in 1 in 100 to 1 in 1000 people. According to the NVKC, 1 in 700 people are IgA deficient without symptoms.

Which medicines can cause an IgA deficiency?

According to MSD, medicines such as phenytoin, sulfasalazine, gold and penicillamine can cause an acquired IgA deficiency in some people.

What does an IgA deficiency mean for a blood transfusion?

According to MSD, with an IgA deficiency antibodies against IgA can develop after a transfusion or other blood products containing IgA. According to MSD, renewed exposure to such products can in rare cases lead to an anaphylactic reaction, a severe allergic reaction.

Total IgA: sources

  1. Star-shl, Labbepalingen (referentiewaarden per bepaling), star-shl.nl, geraadpleegd 2026-10-01 (retrieved 2026) star-shl.nl
  2. Unilabs, Bepalingenklapper (referentiewaarden per bepaling), bepalingenklapper.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenklapper.nl
  3. Certe, Bepalingenwijzer (referentiewaarden per bepaling), bepalingenwijzer.certe.nl, geraadpleegd 2026-10-01 (retrieved 2026) bepalingenwijzer.certe.nl
  4. Diagnostiek voor U, eLabgids (Referentiewaarden DvU), diagnostiek.getincontrol.eu, geraadpleegd 2026-10-01 (retrieved 2026) diagnostiek.getincontrol.eu
  5. NVKC, Zinnige Diagnostiek: coeliakie, 2015, geraadpleegd 2026-10-06 (retrieved 2026) nvkc.nl
  6. Fernandez J. Selective IgA Deficiency. MSD Manual Professional Version, October 2024. (retrieved 2026) msdmanuals.com
  7. MedlinePlus Medical Encyclopedia, Quantitative nephelometry test, medlineplus.gov, review date 2026-05-01, geraadpleegd 2026-10-16 (retrieved 2026) medlineplus.gov
  8. Serum immunoglobulin A levels and alcohol-induced liver disease. Can Liver J 2020;3(2). (retrieved 2026) pmc.ncbi.nlm.nih.gov

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Total IgA

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