Definition

Antibodies, or immunoglobulins, are essential components of the immune system. They are proteins produced by immune cells to help the body fight off foreign invaders, such as viruses and bacteria. When exposed to bacteria or viruses, the body generates antibodies to combat these pathogens. IgA (Immunoglobulin A) accounts for about 15% of the total immunoglobulins in the blood and is also found in saliva, tears, gastric and respiratory fluids, and breast milk (ASI).

IgA plays a crucial role in protecting the body's mucosal areas, such as the respiratory tract (in the sinuses and lungs) and the digestive tract (in the stomach and intestines). When a mother breastfeeds her baby, she passes IgA antibodies through breast milk, which helps protect the baby's digestive system. Since infants do not produce significant amounts of IgA on their own until around 6 months of age, breastfeeding provides essential protection during this period.

IgA exists in two subclasses: IgA1 and IgA2. The IgA test measures the levels of Immunoglobulin A, one of the most common types of antibodies in the body.

Indication

Your doctor may recommend an IgA test to help diagnose issues with the immune system, digestive tract, or kidneys. This test is also used in children who experience frequent infections. It can also be used to investigate autoimmune conditions, where the body mistakenly produces antibodies that attack healthy tissues, such as arthritis, lupus, and Celiac disease. Children with low or absent IgA levels may be at a higher risk of developing autoimmune diseases, infections, asthma, and allergies.

Contraindication

There are no specific contraindications for the IgA test.

Preparation Before the Test

There is no special preparation required before undergoing an IgA test. You do not need to fast before the test. However, it is important to inform your doctor about any medications or foods that may affect the results. Ensure that you are calm and hydrated before the test to help ensure accurate results.

Test Procedure

The IgA test uses a blood sample. To collect the sample, laboratory staff will first clean your arm with sterile alcohol. A small amount of blood will be drawn from a vein using a sterile syringe. In infants, blood is typically drawn from the heel.

If the blood is taken from a vein, the skin will be cleaned with antiseptic, and a special tool (tourniquet) will be placed around the arm to apply pressure and make the blood vessels swell. A needle will then be inserted into the blood vessel, typically in the inner arm, elbow, or back of the hand. The blood will be collected into a vial or syringe. After the procedure, the tourniquet will be removed, and the area where the blood was drawn will be covered with a bandage to stop any bleeding.

The blood sample is then placed into a test tube and analyzed by laboratory staff using specialized equipment. Results from this test may take up to a day to be processed. The risks associated with this test are minimal, though some people may experience mild pain, dizziness, or bruising at the blood draw site. These effects typically resolve quickly. The procedure itself is simple and usually takes about 10 minutes, including the time needed to draw the blood and prepare the sample.

Normal and Abnormal Values

The normal IgA levels in adults typically range between 0.8 to 3.0 g/L. The test values for IgA are age-dependent:

• 0-1 year: 1-83 mg/dL

• 1-5 years: 20-152 mg/dL

• 5-10 years: 33-274 mg/dL

• 10-17 years: 42-378 mg/dL

• Over 18 years: 60-400 mg/dL

Values outside these ranges, either below or above the normal limits, are considered abnormal.

Results and Recommendations (Follow-up Tests)

IgA test results are not conclusive on their own, so your doctor may recommend additional antibody tests, such as IgG and IgM tests, for further evaluation. Elevated IgA levels can indicate several conditions, including allergies, chronic infections, autoimmune disorders such as rheumatoid arthritis, lupus, or Celiac disease, liver disorders, inflammation of the kidneys, and cancers like lymphoma or leukemia.

On the other hand, low or decreased IgA levels may be linked to infections or recurrent infections, complications from diabetes, kidney disorders, kidney failure, HIV/AIDS, and may also be found in infants under 6 months of age.

It’s important to note that both high and low IgA values do not always point to a specific disease, so discussing your test results with your doctor is essential for further interpretation and potential next steps.

Consult the Right Doctor

If your IgA test results are abnormal, you should consult a general practitioner for an accurate diagnosis and appropriate treatment. If necessary, an internist can also be consulted for specialized care. Your doctor may suggest additional tests to confirm the diagnosis and help guide the best course of treatment.

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