A patient presents with bilateral cervical lymphadenopathy, fever, and petechiae on the soft palate. Which diagnostic test should be performed first?

The combination of bilateral cervical lymphadenopathy, fever, and palatal petechiae is the classic triad of infectious mononucleosis (caused by Epstein-Barr virus, EBV). Palatal petechiae at the junction of the hard and soft palate are highly specific for mononucleosis. The Monospot test (heterophile antibody test) is the rapid, first-line diagnostic test for EBV mononucleosis. Other findings include tonsillar exudates, splenomegaly, and atypical lymphocytosis on CBC. Dental significance: patients with mononucleosis may present with significant oral manifestations, and dentists should be aware that regional lymphadenopathy may be oral in origin.