False-Positive Monospot in a Returning Traveler with Dengue Fever

Kimberly Boyd, Joshua M. Harrison, Michael J. Kavanaugh

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The heterophile antibody (Monospot), initial test of choice for Epstein-Barr virus (EBV)-associated infectious mononucleosis, is both sensitive (70-92%) and specific (96-100%). False positives have been demonstrated in cases of viral hepatitis, human immunodeficiency virus, leukemia, lymphoma, pancreatic cancer, systemic lupus erythematosus, and rubella. We present a case of a 46-yr-old male who developed fever, chills, headaches, myalgia, fatigue, and photophobia 1 d after returning from the Philippines. He demonstrated a mild transaminitis and significant thrombocytopenia (12,000 cells/μL). His initial evaluation revealed a positive heterophile antibody test. Without a classic EBV presentation, a fever in returning traveler evaluation was instituted resulting in a positive dengue test by direct fluorescence IgM (8.82 IU) and IgG (7.13 IU), respectively. Both his EBV DNA polymerase chain reaction and IgM by viral capsid antigen were negative. Dengue, an RNA flavivirus, and the dengue antibody have demonstrated cross-reactivity with other flaviviruses including Japanese encephalitis virus, yellow fever virus, West Nile virus, and St. Louis encephalitis. However, EBV is a double-helix DNA herpesvirus and structurally very different. To our knowledge, this is the first reported case of cross-reactivity between dengue and EBV that describes a potential false positive for the heterophile antibody test.

Original languageEnglish
Pages (from-to)E235-E236
JournalMilitary Medicine
Issue number3-4
StatePublished - 1 Mar 2018
Externally publishedYes


  • Dengue
  • Epstein Barr Virus
  • Heterophile antibody
  • Monospot
  • flavivirus


Dive into the research topics of 'False-Positive Monospot in a Returning Traveler with Dengue Fever'. Together they form a unique fingerprint.

Cite this