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Blood Test: Immunoglobulin A (IgA)

Medically reviewed by: Yamini Durani, MD

What Is a Blood Test?

By taking and testing a small sample of a person’s blood, doctors can check for many kinds of diseases and conditions. Blood tests help doctors check how the body’s organs are working and see if medical treatments are helpful.

To help your child get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is anxious about it, work together on ways to stay calm.

What Is an IgA Test?

An IgA test measures the blood level of immunoglobulin A, one of the most common types of antibodies in the body. Antibodies (also called immunoglobulins) are proteins the immune system makes to recognize and get rid of germs.

Normally, high IgA levels are found in the body's mucous membranes, especially the respiratory passages and gastrointestinal tract, and in saliva (spit) and tears.

Why Are IgA Tests Done?

Doctors may order an IgA test to diagnose problems with the immune system, intestines, and kidneys. They’re also done for kids who have recurrent infections. These tests can check for autoimmune conditions in which the body mistakenly makes antibodies against healthy tissues, such as arthritis, lupus, and celiac disease. Kids born with low levels of IgA — or none at all — are at higher risk for autoimmune conditions, infections, asthma, and allergies.

What if I Have Questions?

If you have questions about the IgA test or what the test results mean, talk to your doctor. 

Medically reviewed by: Yamini Durani, MD
Date reviewed: August 2023