A 19-year-old college student presents to the clinic with 7…
A 19-year-old college student presents to the clinic with 7 days of fever, sore throat, malaise, and fatigue. He reports difficulty swallowing and notes that several classmates have been ill recently. He denies cough or rhinorrhea. On physical exam: Temperature: 38.6°C (101.5°F) Oropharynx: tonsillar exudates Neck: posterior cervical lymphadenopathy Abdomen: mild left upper quadrant tenderness Laboratory studies reveal: WBC count: 14,500/µL AST and ALT mildly elevated A rapid antigen detection test for Group A Streptococcus is negative. What is the next step in making a diagnosis?