A 42-year-old woman is evaluated for nausea, anorexia, fever, and malaise that have been present for several days. On physical examination, she has visible scleral icterus. She recently returned from a trip to Honduras, and she did not receive any pretravel medical care or immunizations. As part of her evaluation, tests for viral hepatitis are ordered. You strongly suspect acute hepatitis A virus (HAV) infection. Which one of the following would confirm a diagnosis of acute hepatitis A infection? Negative serum IgM anti-HAV combined with a positive HAV nucleic acid test Positive serum IgM anti-HAV Positive serum IgG anti-HAV A serum alanine aminotransferase level (ALT) greater than 200 IU/dL combined with a positive serum IgG anti-HAV