A 5-year-old patient is suspected of having infectious mononucleosis.The patient's blood smear reveals 55% reactive lymphocytes and a WBC count of 15 × 10⁹/L.The heterophile antibody test is negative.IgG and IgM antibodies to EBV both come back positive.What is the best explanation for these results?

Question

Quizplus · Accepted Answer

A negative heterophile antibody test does not rule out infectious mononucleosis in children under the age of 10, as up to 50% of young children may not produce these antibodies. The presence of both IgG and IgM antibodies to EBV indicates a past infection with the virus, confirming the diagnosis of infectious mononucleosis. Acute lymphoid leukemia would not explain the presence of specific antibodies to EBV. False-positive serologic tests are possible but less likely in this case since both IgG and IgM antibodies were positive.

A 5-Year-Old Patient Is Suspected of Having Infectious Mononucleosis