Mononucleosis Tests

Mononucleosis, also known as mono or the "kissing disease," is a viral infection caused by the Epstein-Barr virus (EBV). The diagnosis of mononucleosis typically involves a combination of physical examination, medical history, and laboratory tests.

Types of Mononucleosis Tests

• Monospot Test: A rapid test that detects the presence of heterophile antibodies in the blood. These antibodies are produced by the immune system in response to an EBV infection.
• EBV Antibody Test: Measures the levels of different types of antibodies against EBV, including IgM and IgG. This test can help determine whether the infection is current or past.
• Complete Blood Count (CBC): Evaluates the different components of blood, including white blood cell count, red blood cell count, and platelet count. People with mononucleosis often have an elevated white blood cell count.
• Liver Function Tests: Assesses liver function and detects any potential liver damage caused by the infection.

How Mononucleosis Tests are Performed

Mononucleosis tests typically involve a blood sample, which is drawn from a vein in the arm. The blood sample is then sent to a laboratory for analysis.

Interpretation of Test Results

The results of mononucleosis tests are interpreted as follows:

• Positive Monospot Test: Indicates the presence of heterophile antibodies and suggests a current EBV infection.
• EBV Antibody Test Results:
  • IgM Positive: Indicates a current or recent EBV infection.
  • IgG Positive: Suggests a past EBV infection.
• Abnormal CBC Results: May indicate an elevated white blood cell count, which is common in people with mononucleosis.

Limitations and Potential False Negatives

Mononucleosis tests are not always accurate, and false negatives can occur. The Monospot test may be negative in the early stages of the infection or in some individuals who do not produce heterophile antibodies. The EBV antibody test may also be negative if the infection is very recent or if the individual has a weakened immune system.