MONOTEST positive or negative: meaning of the rapid test for the diagnosis of mononucleosis, indications and cost

The monotest is a quick test for diagnosing mononucleosis, a infectious disease caused by the Epstein Barr virus (EBV). A positive monotest, in the presence of typical symptoms such as fever, loss of appetite and swollen lymph nodes, it is highly indicative of the presence of mononucleosis.


The Monotest is a test for the mononucleosis, used to quickly and sufficiently reliably diagnose this infectious disease. It's a quick test and from low price (the cost of the single test is usually less than 10 euros).

Normal values Monotest

The normal value of the Monotest is negative.


Monotest for the diagnosis of mononucleosis, Epstein Barr Virus infection

Mononucleosis Diagnosis

There infectious mononucleosis is caused by a type of herpesvirus, the Epstein-Barr virus. It is a frequent disease especially in children and young people.

Diagnosis of mononucleosis involves the presence of the most common symptoms, such as general malaise, fatigue, sore throat (pharyngodynia), fever, inflammation of the pharynx (pharyngitis), swelling and soreness of the lymph nodes (lymphadenopathy), enlargement of the spleen (splenomegaly) and liver (hepatomegaly), and the presence of an increase in white blood cells (lymphocytosis), which may appear enlarged on microscopic analysis of the blood (called reactive lymphocytes, activated lymphocytes or 'virocytes').

Infection with Epstein Barr Virus (EBV) in most cases it is one self-limiting disease low risk of complications, in the sense that it does not require specific therapy, but only treatments to relieve and control symptoms while waiting for it to resolve on its own. In general it is characterized by a modest increase in C reactive protein and is not dangerous, but in some situations the symptoms can worsen rather than resolve, especially if the infection affects a person with adult or advanced age.

Infectious mononucleosis stimulates the production of a particular type of antibody, the heterophile antibodies IgM type (immunoglobulin M). These antibodies form within one week of the onset of the disease (usually between the 4th and 7th day of infection), and reach their maximum amount in the blood between the second and fifth week. Their presence can also be documented up to 1 year after infection.

The heterophile antibodies they are recognized thanks to the characteristic of being able to make mutton or horse red blood cells agglutinate, and this is precisely the principle used to perform the Monotest.

They are not antibodies directed specifically towards theEpstein Barr Virus, but they are found very frequently in patients with monucleosis, and in the presence of the symptoms and the typical clinical picture, they allow a rapid diagnosis to be made in a good number of people.

In fact, for the diagnosis of mononucleosis it is measured with the single test the titer of heterophile antibodies (HAT, heterophile antibody titer), which turns out positive in 90% of mononucleosis cases, although it should not be forgotten that the IgM-type hererophilic antibodies can also be found in other conditions other than infection by the Epstein-Barr virus.

Furthermore, a small percentage of people with mononucleosis do not produce heterophile antibodies, making the Monotest negative even in the presence of infection.

For the diagnosis of atypical pictures, if the search for heterophile antibodies is negative, it is possible to search for the presence of the Epstein-Barr virus in the blood through specific tests that isolate IgM and IgG antibodies, or in doubtful cases, directly through the search for DNA in the virus in the blood.

Monotest how to do it

 How the Monotest is performed? The Monotest is a simple one blood test, which is done by taking a tube of blood, usually from a vein in the hollow of the arm. The analysis of the presence of heterophile antibodies in the collected blood allows, if positive, to make a diagnosis of Mononucleosis with excellent semsibility and specificity.

Positive single test

There diagnosis of mononucleosis can be done in case of Positive single test and presence of typical symptoms of mononucleosis with changes in blood tests blood count, such as increased white blood cells and reactive lymphocytes.

There are cases where the Monotest gives results false positives: it should not be forgotten that there are some diseases, other than mononucleosis, in which a high level of heterophile antibodies can be found, such as blood diseases, rheumatological diseases such as Systemic Lupus Erythematosus (SLE), and neoplasms.

Here is a list of the most frequent conditions with Positive single test but absence of mononucleosis:

  • Burkitt's lymphoma
  • Nasopharyngeal carcinoma
  • Neoplasms of the pancreas
  • Hodgkin's lymphoma
  • Lymphatic leukemia
  • Systemic lupus erythematosus
  • Rheumatoid arthritis
  • Sarcoidosis
  • Chronic fatigue syndrome
  • Interference linked to a cytomegalovirus (CMV) infection
  • Chronic infection by Epstein-Barr virus (EBV)
  • Malaria
  • Rubella infection
  • Viral hepatitis

Negative single test

If i typical symptoms of mononucleosis, with changes in blood tests such as the increase in white blood cells and the presence of reactive lymphocytes, but the Monotest is negative, the diagnosis of mononucleosis it cannot be excluded. In such cases, the test may have been done too early, when the heterophile antibodies have not yet formed.

In other cases, you may be faced with a small percentage of people who do not develop heterophile antibodies (atypical mononucleosis), and it is therefore possible to repeat the test or perform more in-depth analyzes such as the search for the Epstein-Barr virus in the blood through specific tests that isolate IgM and IgG antibodies or DNA directly in the virus.

If, on the other hand, in addition to the Negative single test, the classic alterations of blood tests are missing (e.g. absence of reactive lymphocytes or virocytes), it is possible that the symptoms are actually due to an infection of other viruses (e.g. cytomegalovirus (CMV) or toxoplasma); this is very important to understand if the sick person is a pregnant woman, because toxoplasma and CMV can cause damage to the fetus, and their presence must be checked immediately for initial therapy.

In other cases, the clinical picture could be caused by a bacterium, such as streptococcus, which can give symptoms very similar to those of mononucleosis. In this case it is important to perform a throat swab (throat swab) and initiate adequate antibiotic therapy.

In case the Monotest is not conclusive, the diagnosis of mononucleotic infection can be established by finding high levels of IgM and IgG antibodies directed to EBV in the blood. IgG antibodies become positive 3-8 weeks after the first EBV virus infection, and then remain positive for a very long time, theoretically for life.

IgM antibodies are usually negative, and become positive after a few days of contact with the virus, and then disappear within 3-6 weeks of the onset of the disease.

Please note: the Monotest for the diagnosis of infectious mononucleosis should not be confused with the VIRCLIA IgG Monotest, the rapid test for the diagnosis of Helicobacter Pylori infection. They are both quick tests, but they identify very different infections!

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