A 28-year-old man from rural India presents with jaundice, dark urine, and abdominal pain for 5 days. He has no history of intravenous drug use, tattoos, or sexual contact with known hepatitis B carriers. Liver function tests show ALT 2800 IU/L, AST 2200 IU/L, bilirubin 8.2 mg/dL, and INR 1.1. HBsAg is negative. Anti-HAV IgM is positive. What is the most appropriate next step in management?