Antibody to Epstein-Barr Nuclear Antigen A (IgG) - Serum

This test measures IgG antibodies that your immune system makes against Epstein-Barr virus nuclear antigen, known as EBNA. A positive result shows that your body has encountered the Epstein-Barr virus in the past, which helps your doctor tell the difference between an older, resolved infection and one that started recently.

The test detects IgG antibodies specific to Epstein-Barr Nuclear Antigen A (EBNA A), a protein produced by the Epstein-Barr virus. These antibodies appear in your blood after your immune system has encountered the virus. The presence of these antibodies indicates a past or ongoing infection, though IgG alone doesn’t distinguish between acute or chronic infection.

Doctors order this test when patients have symptoms such as lasting tiredness, fever, sore throat, or swollen lymph nodes, or when earlier Epstein-Barr virus results need to be clarified. It helps confirm a past infection and rule out other conditions that can cause similar complaints.

Healthcare providers may order this test to diagnose or monitor Epstein-Barr virus infections, such as infectious mononucleosis, or to evaluate conditions like chronic fatigue syndrome, lymphoproliferative disorders, or in certain autoimmune diseases where EBV is suspected. It can also be used in research or for screening in high-risk populations.

The sample is a small amount of blood drawn from a vein in your arm, usually at a laboratory or clinic. Little or no preparation is needed, and you may normally eat, drink, and take your regular medicines. Let the person drawing your blood know if you bruise easily or take blood thinners.

A blood sample is drawn from a vein in your arm. The blood is processed to separate serum (the liquid part without clotting factors) for testing. This serum is then analyzed to detect the presence of EBNA IgG antibodies using an immunoassay method.

Before the test, a healthcare professional will explain the procedure and answer your questions. An elastic band is placed around your upper arm so the vein is easier to see, and the blood draw itself takes only a few minutes. Most people can return to their normal activities right away.

There are no special preparations needed for this test. You may have some mild discomfort or bruising at the injection site, but this usually resolves quickly. If you’re on blood-thinning medication or have a history of bleeding disorders, let your provider know before the test.