Question 1

How accurate is the mono test?

Accepted Answer

The heterophile antibody test has a sensitivity of 87% and specificity of 91% but can have a false-negative result in children younger than five years and in adults during the first week of illness. While generally reliable, the test may miss some cases of mono, particularly in very young children or if testing is done too early in the infection.

Question 2

Can I have mono even if the test is negative?

Accepted Answer

Yes, it is possible to have mono with a negative test result. Ten percent of cases of true EBV mononucleosis may have negative heterophile antibodies. This is particularly common in young children and if testing is done very early in the illness. EBV-specific antibody testing may be recommended if mono is still suspected.

Question 3

When is the best time to get tested for mono?

Accepted Answer

Detectable levels of the infectious mononucleosis heterophile antibody can usually be expected to occur between the sixth and tenth day following the onset of symptoms, with the level usually increasing through the second or third week of illness. Testing too early in the infection may result in a false negative result.

Question 4

How long do mono antibodies stay in the blood?

Accepted Answer

Infectious mononucleosis heterophile antibody titers have been shown to persist in some cases for months to years after clinical symptoms have subsided. This means that a positive test may indicate either a current infection or past exposure to the virus.

Question 5

What other conditions can cause a positive mono test?

Accepted Answer

The heterophile antibody has been associated with several diseases other than mono, including leukemia, Burkitt lymphoma, pancreatic carcinoma, viral hepatitis, cytomegalovirus infections, and others. This is why clinical correlation with symptoms is important for proper interpretation of results.

Question 6

Is the mono test different from EBV-specific antibody testing?

Accepted Answer

Yes, the mono test detects heterophile antibodies that are produced in response to various infections, while EBV-specific antibody tests detect antibodies specifically directed against Epstein-Barr virus proteins. Serum testing for EBV-specific antibodies is considered the gold standard for diagnosis, but rapid results are usually not obtainable. EBV-specific testing may be recommended if the mono test is negative but mono is still suspected.

Mononucleosis (Mono) Test