Immunoglobulin A (IgA) in Serum

What Is Immunoglobulin A (IgA)?

Immunoglobulin A (IgA) is a key part of your immune system. It’s the most common antibody in your blood and is also found in mucus, saliva, and tears. IgA helps protect your body from infections by binding to pathogens (like bacteria and viruses) before they can cause harm. It plays a role in preventing infections in places like your lungs, digestive tract, and respiratory system.

Why Might You Need This Test?

Your doctor may order an IgA test to check for immune system issues, such as low IgA levels, which could be linked to conditions like immunodeficiency disorders, certain autoimmune diseases, or digestive problems. It may also be used to monitor treatment responses or investigate symptoms like frequent infections, chronic diarrhea, or unexplained skin rashes.

Common Reasons for Testing

Common reasons include diagnosing or monitoring conditions like common variable immunodeficiency (CVID), celiac disease, or other immune-related disorders. It may also be part of a broader evaluation for recurrent infections, especially if they involve the respiratory or gastrointestinal tract.

What to Expect Before the Test

No special preparation is usually needed for this test. You may have a small needle inserted into your arm to draw blood. If you’re concerned about blood draws, let your healthcare provider know so they can provide comfort measures.