From the Guidelines
The primary test for mononucleosis (mono) is a blood test called the Monospot test or heterophile antibody test, which detects antibodies that form during infection with the Epstein-Barr virus (EBV), the most common cause of mono. This test can be performed in a doctor's office with results available within minutes 1. If the Monospot test is negative but mono is still suspected, more specific blood tests may be ordered, including an EBV antibody panel that can detect different types of antibodies to confirm recent or past infection 1.
Key Points to Consider
- The Monospot test is a rapid and convenient test that can be used to diagnose mono, but it may be falsely negative in some cases, particularly in young children or early in the illness 1.
- A complete blood count (CBC) is often performed to check for an elevated white blood cell count with an increased number of atypical lymphocytes, which is characteristic of mono 1.
- Blood tests may also help rule out other conditions with similar symptoms, such as cytomegalovirus (CMV) infection 1.
- The Monospot test and EBV antibody panel require a simple blood draw and are generally accurate, but it's essential to consider the limitations and potential false negatives when interpreting the results 1.
From the Research
Test for Mono
The test for mono, also known as infectious mononucleosis, typically involves a blood test to detect the presence of heterophile antibodies or Epstein-Barr virus (EBV) specific antibodies.
- The monospot test is the most widely used method to detect serum heterophile antibodies of infectious mononucleosis 2.
- When confirmation of the diagnosis of infectious mononucleosis is required in patients with mononucleosis-like illness and a negative mono-spot test, serologic testing for antibodies to viral capsid antigens is recommended 2.
- The EBV-specific IgM antibody technique is also a promising method for diagnosing recent infections, as it enables diagnosis on the basis of only one serum specimen 3.
- Other tests, such as the plasma EBV-DNA test and the EBV viral capsid antigen (VCA)-IgG avidity test, also have high diagnostic value for infectious mononucleosis 4.
Diagnostic Value of Tests
The diagnostic value of these tests can vary depending on the age of the patient and the stage of the disease.
- The plasma EBV-DNA test has a higher diagnostic value than the VCA-IgG avidity test in children aged <6 years, especially those aged <3 years 4.
- The peripheral lymphocyte test and plasma EBV-DNA test are suitable for the early stage of the disease, while the VCA-IgG avidity test is more suitable for after 7 days of the disease 4.
- EBV antibody detection should be combined with EBV nucleic acid detection in children aged <6 years and in the early stage of the disease 4.
Antibody Responses
Antibody responses to EBV can also be used to diagnose infectious mononucleosis.
- Antibodies to EBNA-2 arise first and decline again in time to lower persistent or even nondetectable levels, while antibodies to EBNA-1 emerge several weeks or months after anti-EBNA-2 and persist indefinitely 5.
- The ratios between the anti-EBNA-1 and anti-EBNA-2 titers can be used to diagnose infectious mononucleosis and distinguish it from chronic EBV infections 5.