Epstein-Barr virus (EBV): VCA, EBNA and PCR

Have you been tired for weeks after a high fever, severe sore throat and swollen lymph nodes in your neck? The most common cause of these symptoms in young people is Epstein-Barr virus (EBV), which causes infectious mononucleosis. EBV antibody testing shows whether you have a recent infection or recovered from the virus long ago, while PCR detects the virus itself in blood.

Who the test is for

• adolescents and young adults with fever, severe sore throat, enlarged lymph nodes and marked fatigue;
• children with suspected mononucleosis, because their rapid test is often negative;
• people with a negative rapid mononucleosis test, when suspicion remains;
• people with tonsillitis that does not resolve with antibiotics or a rash after amoxicillin treatment;
• people with an enlarged spleen, elevated liver enzymes or changes in the blood count of unclear cause;
• people with weakened immunity, in whom a doctor sometimes requests PCR.

If you have difficulty breathing or cannot swallow saliva, or develop sudden severe abdominal pain on the left below the ribs, call emergency medical services immediately (194 or 112).

What the test reveals

EBV spreads through saliva, and most people become infected by adulthood, often without symptoms. The virus then remains in the body for life. Antibodies develop at different times, so their combination shows the infection phase:

• VCA IgM develop early and usually disappear within four to six weeks.
• VCA IgG develop during the acute phase and remain for life.
• EBNA IgG develop only two to four months after illness begins and remain for life.
• PCR detection of Epstein-Barr virus detects the virus in blood. It is not the first choice for ordinary mononucleosis, but is used in special situations, such as weakened immunity.

The procedure and preparation

For antibodies, blood is drawn from a vein, taking a few minutes. Fasting is not required, and a blood count can be performed from the same draw. PCR also uses a blood sample. State when symptoms began, because this helps interpretation.

What your result means

• All antibodies negative: you have not been infected with EBV or are at a very early stage. If symptoms persist, a doctor may repeat the test or request antibodies to CMV.
• VCA IgM and VCA IgG positive, EBNA IgG negative: recent infection, most often mononucleosis.
• VCA IgG and EBNA IgG positive, VCA IgM negative: past infection, as in most adults, so current symptoms probably have another cause.
• All three positive or only VCA IgG positive: a later stage of recent infection, viral reactivation or past infection. A doctor assesses this, sometimes with repeat testing.
• PCR positive: the virus was detected in blood, and the significance depends on immunity and symptoms.

A doctor interprets the result alongside examination, blood count and other findings.

How to arrange testing

You can have blood taken without an appointment or referral at one of our branches across Croatia (listed under Contact). Prices for all tests and panels are available in the price list. For all three antibodies, the more cost-effective option is the Infectious mononucleosis panel (Epstein-Barr virus), and when a doctor also wants to check CMV, the Infectious mononucleosis + CMV panel.

Frequently asked questions

I have positive EBV IgG. Am I ill?

Not necessarily. Around 90 % of adults have had EBV, so most healthy people have VCA IgG and EBNA IgG. Without VCA IgM, this result indicates an old infection and usually does not explain current fatigue.

When is the right time for testing?

When you have symptoms. VCA antibodies are usually measurable at illness onset, while EBNA IgG is expected to be negative then. If the result is unclear, a doctor may repeat the test after a few weeks.

When is EBV PCR performed?

Antibodies are sufficient for ordinary mononucleosis. A doctor requests PCR in special situations, such as weakened immunity or when antibodies do not provide a clear answer.

Does the test show that mononucleosis has resolved?

Not directly, because VCA IgG and EBNA IgG remain for life. A doctor assesses recovery according to symptoms, examination, blood count and liver enzymes. Read more about the disease and recovery in the article Infectious mononucleosis – symptoms, tests and interpretation.