Immunoglobulin A Test - IgA

The immunoglobulin A (IgA) test is a blood test that measures the level of IgA, one of the antibodies your immune system uses to defend the body against infection. Immunoglobulins are proteins made by plasma cells and lymphocytes that recognise and help destroy foreign invaders such as bacteria and viruses. There are five main types: IgA, IgD, IgE, IgG, and IgM, and each has its own role.

IgA is especially important at the body's mucosal surfaces: the linings that come into contact with the outside world. It is found in the gut, saliva, tears, breast milk, and the respiratory tract, where it forms a first line of defence and helps prevent germs from taking hold. IgA makes up roughly 10 to 15% of all the antibodies in the body.

Doctors order an IgA test to help diagnose problems with the immune system. The test is also useful in investigating recurrent infections of the lungs, sinuses, intestines, or stomach, and in conditions such as coeliac disease and IgA nephropathy, a kidney disease in which IgA builds up in the kidneys.

Your doctor may recommend an IgA test when there are signs of an immune system disorder, recurrent infections, or suspected abnormal antibody production.

• Recurrent infections of the lungs, sinuses, intestines, or stomach.
• Persistent or chronic diarrhoea.
• Recurrent fevers with no obvious cause.
• Suspected immune deficiency, including selective IgA deficiency.
• Autoimmune conditions such as rheumatoid arthritis, lupus, or coeliac disease.
• Suspected IgA nephropathy (a kidney condition).
• Assessment of immune function in people living with HIV/AIDS.

The IgA test is suitable for people of any age and gender. It is often ordered together with IgG and IgM as part of a full immunoglobulin assessment.

The IgA test is ordered when there are signs of chronic inflammation, recurrent infections, or suspected abnormal immunoglobulin production. When monitoring an ongoing condition, your doctor may repeat it from time to time to follow the course of your illness or your response to treatment.

By measuring IgA, the test helps your doctor assess immune function and investigate a range of conditions:

Your IgA result is interpreted with your age, symptoms, and other tests. The general patterns are:

A high or low IgA level is a clue, not a diagnosis. Your doctor will combine it with other immunoglobulins and specific tests, for example, coeliac antibodies, kidney tests, or protein studies, to identify the underlying cause.

Disclaimer: This information is for educational purposes and provides a risk assessment only. It does not confirm a diagnosis. Always consult your doctor to understand how your IgA result relates to your overall health.

The IgA test measures a single parameter: the level of immunoglobulin A in your blood, reported in mg/dL. The result is a number rather than a positive or negative.

• Immunoglobulin A (IgA): the antibody that protects mucosal surfaces such as the gut, airways, saliva, and tears. A higher- or lower-than-normal value indicates a possible disorder of the immune system.

To build a fuller picture of immune function, your doctor often orders IgA together with IgG and IgM as a complete immunoglobulin profile.

BRI : Adult : 0.40 - 3.50 g/L

Important note: Reference ranges may vary between laboratories. Always refer to the range printed on your own report and consult your doctor for interpretation.

Your IgA result is interpreted with your age, symptoms, and other tests. The general patterns are:

A high or low IgA level is a clue, not a diagnosis. Your doctor will combine it with other immunoglobulins and specific tests, for example, coeliac antibodies, kidney tests, or protein studies, to identify the underlying cause.

Disclaimer: This information is for educational purposes and provides a risk assessment only. It does not confirm a diagnosis. Always consult your doctor to understand how your IgA result relates to your overall health.

The IgA test is a routine blood draw that is generally very safe, with minor procedural risks and some limitations.

Potential Risks and Complications

Risks from a blood test are very low; most people feel only slight pain or bruising at the needle site, which settles quickly. Consult your doctor if you notice:

• Persistent bleeding at the puncture site that does not stop with gentle pressure.
• Redness, swelling, or pain at the needle insertion site.
• Light-headedness that continues after the blood draw - sit and rest before leaving.

Understanding IgA Test Limitations

• A high or low IgA level alone does not diagnose a specific disease; further tests are needed.
• Results can be affected by infections, medicines, and other conditions present at the time.
• IgA is best interpreted alongside IgG and IgM as part of a full immunoglobulin profile.
• Reference ranges differ between labs, so results may not be directly comparable.

If your IgA result is abnormal, your doctor may recommend additional tests to find the cause.