Immunoglobulin A (Iga), Serum

Immunoglobulin A (IgA), Serum

What it is

The Immunoglobulin A (IgA), Serum test measures the level of IgA antibodies in the blood. IgA is one of the five major classes of immunoglobulins (antibodies) and plays a critical role in protecting mucous membranes of the respiratory tract, digestive system, and urinary tract. Abnormal IgA levels can indicate immune deficiencies, autoimmune conditions, chronic infections, or certain blood cancers.

Uses

This test is used to:

• Evaluate overall immune system function.
• Identify IgA deficiency, which can increase susceptibility to infections.
• Assist in the diagnosis of celiac disease (along with tissue transglutaminase IgA).
• Support diagnosis of autoimmune disorders and chronic infections.
• Monitor patients with multiple myeloma or other immunoglobulin-related disorders.

Symptoms / Conditions That May Lead to the Test

Doctors may recommend this test if you have:

• Frequent respiratory or gastrointestinal infections.
• Chronic diarrhea, malabsorption, or symptoms suggestive of celiac disease.
• Unexplained autoimmune symptoms (e.g., joint pain, rashes, fatigue).
• Family history of immunodeficiency disorders.
• Signs of blood cancers such as multiple myeloma or lymphoma.

Abnormal Results

• Low IgA Levels: May indicate selective IgA deficiency, a common immune disorder, or other immunodeficiencies. Can increase risk of infections and allergic disorders.
• High IgA Levels: May suggest chronic infections, autoimmune diseases (e.g., rheumatoid arthritis, lupus), liver disease, or multiple myeloma.
• Normal IgA Levels: Usually indicate healthy immune function, but other tests may still be needed if symptoms persist.

Results are interpreted with other immunoglobulin levels, clinical findings, and additional laboratory tests.

Risks

The test requires a blood sample and carries minimal risks, including:

• Mild pain, bruising, or discomfort at the puncture site.
• Rare risk of infection or dizziness after blood draw.