To get screened for/to diagnose infectious mononucleosis (glandular fever).
If you have symptoms of mononucleosis, including fever, sore throat, swollen glands, and fatigue. (The monospot test is not useful to detect Epstein-Barr virus (EBV) in children less than four years old of age.)
A blood sample taken from a vein in your arm
No test preparation is needed.
The Monospot test detects heterophile antibodies produced by the immune system in response to Epstein-Barr virus (EBV) infection. These antibodies can cross-react with other types of cells, including horse red blood cells (the ones used in the monospot). A similar test, the Paul-Bunnell test, detects a reaction with sheep red blood cells instead. EBV causes infectious mononucleosis (glandular fever), a self-limiting disease.
Mononucleosis is characterised by the presence of atypical white blood cells (atypical lymphocytes) in an infected person. EBV causes these symptoms: fever, sore throat, swollen glands, and fatigue. About 70%–80% of people with infectious mononucleosis produce these heterophile antibodies, which are not specific for EBV infection but are a good predictor of EBV infection.
How is it used?
The Monospot test is used to determine whether you have infectious mononucleosis. This test is rapid and easy to perform, but it is not 100% specific. More testing may be needed to confirm that the disease is mononucleosis and not another illness. However, due its practicalities, the heterophile test remains the diagnostic point-of-care test of choice in many clinical settings.
When is it requested?
The Monospot test is requested if your doctor suspects that you have infectious mononucleosis, which causes fever, headache, swollen glands, tiredness, and malaise. Your healthcare professional may detect that you have an enlarged spleen or liver.
The test will not be positive until you have been infected for about two weeks. Other tests may need to be requested if the heterophile antibodies are negative (in particular if you are still within the first week of the disease), but your doctor still suspects mononucleosis as the cause of your symptoms.
Other blood tests that are more specific to the EBV can be used to find early infection or to confirm mononucleosis. These tests include the IgM and IgG antibodies to the viral capsid antigen (VCA), which can be found early in the disease. VCA IgM is only present in the few weeks after infection, but the IgG antibodies can also be found later, during recovery. Antibodies to Epstein-Barr virus Nuclear Antigen (EBNA) may also be tested for to gain a more accurate indication of recent or previous EBV infection.
What does the test result mean?
A positive result in the Monospot test, together with symptoms of mononucleosis, is the basis for a diagnosis of infectious mononucleosis. In addition to a positive reaction on the Monospot test, an infected person has a higher white blood cell count, with a higher than usual number of atypical lymphocytes. Heterophile antibodies decline after the fourth week of illness, and the Monospot test will become negative as the infection resolves.
A negative test result means that a person may not have mononucleosis or that it is too early in the illness to detect the antibodies. The test may need to be repeated if symptoms remain. Infants and young children (in particular less than four years old of age) do not make heterophile antibodies when infected with EBV, so more specific viral tests must be used to make the diagnosis.
Interpretation of Specific EBV Test results
EBV IgM antibody EBV IgG antibody EBNA antibody Interpretation Positive Negative Negative Recent EBV infection Positive Positive Negative Recent EBV infection Negative Positive Positive Previous EBV infection
Is there anything else I should know?
In young adults, an effective laboratory diagnosis can be made on a single blood sample during the acute phase of the disease with a Monospot test. By requesting the more extensive battery of EBV blood tests, the healthcare professional will also be able to learn whether a person is susceptible to EBV, has had a recent infection, has had EBV infection in the past, or has a reactivated EBV infection.
When the Monospot test is negative, a combination of EBV antibody tests for IgM and IgG to the viral capsid antigen, IgM to the early antigen, and IgG antibody to the nuclear antigen may be requested, as well as antibody tests for cytomegalovirus (CMV) or Toxoplasma gondii.
How serious is infectious mononucleosis?
The symptoms of the disease usually resolve without treatment in one to four months. Sometimes, your spleen or liver may enlarge, and you may have to limit your physical and sport activities until these organs return to normal size. Heart problems or involvement of the central nervous system are very rare. Infectious mononucleosis may cause severe liver failure in males with a very rare and inherited X-linked lymphoproliferative (XLP) syndrome immunodeficiency disorder characterized by a defective immune system.
Is mononucleosis really a "kissing disease"?
The spread of EBV requires intimate contact with saliva (found in the mouth) of an infected person. Kissing can transmit infection, but saliva on toys, drink containers or hands can also transmit the virus. Transmission through the air or blood does not normally occur. The incubation period, the time from infection to appearance of symptoms, ranges from 4 to 6 weeks.
People who have infectious mononucleosis may be able to spread the infection to others for a period of weeks. Many healthy people can carry and spread the virus intermittently for life, and testing them for the virus is not practicable. For this reason, it is almost impossible to prevent the spreading of the virus.
Does Epstein-Barr virus cause chronic fatigue syndrome?
There is no laboratory evidence indicating that EBV infection causes chronic fatigue. However, it is very normal to feel very tired during the infection period and for one or two months after the infection. For more information, visit the Centers for Disease Control and Prevention’s website.
Can I get infectious mononucleosis more than once?
Although the symptoms of infectious mononucleosis usually go away in 1 or 2 months, EBV remains inactive in a few cells in the body for the rest of the person's life. Periodically, the virus can reactivate, and it is commonly found in the saliva of infected persons, particularly if they are immunosuppressed. This reactivation usually occurs without symptoms of illness.
Can EBV cause other serious illnesses?