• Epstein-Barr virus (EBV) is a common herpes virus that causes most cases of glandular fever.
• To diagnose glandular fever, your doctor will order blood tests to detect antibodies your immune system makes to the virus.
• Different antibody types can show if you have a current, recent or a past viral infection.

Epstein-Barr virus (EBV) is a common herpes virus that is the cause of most cases of glandular fever (infectious mononucleosis). As many as 95 per cent of adults in the world have been infected at some point in their lives.

EBV mostly infects children and young adults. Children usually have no symptoms. However, when the infection occurs in adults it causes glandular fever in up to half of those infected. Glandular fever is the term given to an infection of the glands and it can also occasionally be caused by other viruses such as cytomegalovirus (CMV), toxoplasmosis, Human Immunodeficiency Virus (HIV) and adenovirus.

Once someone has been exposed to EBV there is an incubation period of several weeks before symptoms start. Many people have no symptoms or only mild symptoms. However, in some people, symptoms can last for weeks or months. These include tiredness, fever, sore throat, swollen lymph nodes, an enlarged spleen and sometimes an enlarged liver.

The virus stays in the body for the rest of that person's life and can become active again from time to time usually causing only mild symptoms.

In diagnosing glandular fever, your doctor will typically start with an examination and assess your symptoms. They will order blood tests that detect antibodies to the virus.

These tests measure the amount of EBV antibodies that your body produces as a response to the virus. Your immune system protects you by making antibodies to attack substances that are foreign to your body and could be harmful to you.

Typically, your doctor will also order a full blood count, and a white cell count with a white cell differential. Glandular fever can cause higher levels of white cells and lower numbers of platelets in your blood. They may also order tests for inflammation such as a CRP and/or ESR and liver function tests. Glandular fever can cause some liver enzymes to rise.

A screening test known as a Monospot is sometimes used. However, this test has been largely replaced by the more accurate antibody tests. The Monospot test can produce false positives and false negatives test results, making it unreliable for accurate diagnosis, especially in children and in the early stages of the illness. The Monospot test detects non-specific antibodies called heterophile antibodies which can be caused by many other infections and autoimmune disorders and so it cannot directly confirm EBV infection.

EBV infection can have similar symptoms to infection by other viruses such as CMV, toxoplasmosis, hepatitis and HIV. The treatment of EBV is different to treatment for these other infections and so knowing what virus is causing your symptoms is important. This is particularly important in pregnancy as some other viruses can cause serious complications.

EBV Antibodies

All cells have markers called antigens on their surface. These antigens act as identification tags, allowing cells to be recognised by other cells. Your immune system protects you by attacking infections and other substances that are foreign to your body and could be harmful to you. It does this by targeting cells with marker antigens that are different from your own.

There are different antigens associated with EBV which are recognised by different antibodies.

Testing for EBV looks for IgM and IgG antibodies to the viral capsid antigen (VCA) present on the virus surface and antibodies to the nuclear antigen (EBNA), which is a molecule within cells that can trigger an immune response.

• The VCA-IgM antibody is usually detectable at the time of the first blood test when symptoms first appear and then tends to disappear between four and six weeks.
• The VCA-IgG antibody develops soon after VCA-IgM and persists for life.
• The EBNA antibody usually develops at between two and four months after the initial infection, so does not usually appear until the acute infection has resolved and then it persists for life.
• EA-D IgG is another IgG antibody against EBV. It usually appears during the early phase of infection and appears within the first month of symptoms and disappears within 3–6 months.
• Persistent or recurrent EA-D IgG may indicate EBV reactivation.

Using a combination of these EBV antibody tests together with your symptoms, your doctor can diagnose an EBV infection and assess whether it is current, recent, or has occurred at some time in the past.

Sample

Blood.

Any preparation

None.

• If you have positive VCA-IgM antibodies it is likely that you have a current or very recent EBV infection. If you also have symptoms, it is likely that you will be diagnosed with an EBV infection.
• If you also have a positive VCA-IgG test result it is highly likely that you have or recently had an EBV infection.
• If the VCA-IgM is negative but the other antibodies including EBNA antibody are detected it is likely that you had a previous EBV infection.
• If you have no symptoms and have a negative VCA-IgG test, then you have not been previously exposed to EBV and could now be infected.

Other antibodies can be raised during an EBV infection including:

• IgG antibody to EBV-D early antigen (EA-D IgG) is not routinely used to check if EBV has come back or become long term.
• IgA antibody to the EBV viral capsid antigen (EBV VCA-IgA).
• IgG antibody to the EBV early antigen restricted (EA-R IgG).

Although it is possible to test for these antibodies as part of the EBV diagnosis it is rarely necessary to do so.

There are molecular tests that can detect and measure EBV DNA. They can be helpful in diagnosing and monitoring EBV-related diseases such as Burkitt's lymphoma, Hodgkin's lymphoma and post-transplant lymphoproliferative disease (PTLD).

A VCA-IgG test, and sometimes an EBNA test, may be ordered for someone who does not have symptoms to decide if they have been previously exposed to EBV or have an EBV infection. This is not routinely used but may be ordered when someone who is at greater risk such as an adolescent or an immune-compromised person, has been in close contact with someone with glandular fever.

You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.

Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:

• Why does this test need to be done?
• Do I need to prepare (such as fast or avoid medications) for the sample collection?
• Will an abnormal result mean I need further tests?
• How could it change the course of my care?
• What will happen next, after the test?
  

Get further trustworthy health information and advice from healthdirect.