What test should be ordered next for a 19-year-old girl with a sore throat and lymphadenopathy after a negative rapid test for IM antibodies?

In the context of a 19-year-old girl presenting with a sore throat and lymphadenopathy, the next appropriate test to order after a negative rapid test for infectious mononucleosis (IM) antibodies is an EBV serological panel. This is because the negative rapid test does not completely rule out infectious mononucleosis, which is commonly caused by the Epstein-Barr virus (EBV).

The EBV serological panel can provide a more comprehensive assessment of the patient's exposure to the virus and the nature of the infection. It typically includes tests for various antibodies, such as the VCA (viral capsid antigen) IgM and IgG antibodies, and the EA (early antigen) antibodies. The timing of the development of these antibodies can confirm a current or past infection with EBV, which is important for diagnosing infectious mononucleosis accurately.

The other options may be relevant in different clinical scenarios, but they do not address the immediate need to investigate the potential for infectious mononucleosis due to EBV, which fits the symptoms presented. Hepatitis testing, while important, is not the immediate focus given the symptomatology. HIV confirmatory testing, though crucial in certain clinical contexts, is not the primary concern based on