MEDizzy - A 24-year-old woman presents to the clinic with fatigue,

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Infections due to Neisseria and others

A 24-year-old woman presents to the clinic with fatigue, fever, sore throat, and puffy eyes. On examination, she is found to have lymphadenopathy and mild hepatosplenomegaly. She remembers having mononucleosis in college. How would you interpret a positive heterophile antibody test result in this patient?

ExplanationMore than 90% of adolescents and adults with primary infectious mononucleosis test positive for heterophile antibodies. The monospot test is commonly used to test for heterophile antibodies. Patients test positive for 3 to 4 months after the onset of illness, and heterophile antibodies may persist for up to 9 months. Although CMV mononucleosis is often difficult to differentiate clinically from other forms of mononucleosis, patients with other forms of mononucleosis rarely test positive for heterophile antibodies. Heterophile antibodies can also be found in patients with rheumatoid arthritis, although this patient's current symptoms are not consistent with this diagnosis. The heterophile titer does not correlate with the severity of the illness.