The most likely diagnosis is Wilson disease. Wilson disease is a rare congenital disorder of copper excretion that occurs in approximately 1 in 30,000 live births. Young patients with Wilson disease tend to present with acute liver failure; older patients present with chronic liver disease and/or neurologic manifestations. Wilson disease should be considered in all patients younger than 40 years of age who have unexplained liver disease. When Wilson disease causes acute hepatitis, usually in young patients, the sudden release of copper from liver cells can also induce hemolytic anemia. This patient's low hemoglobin level, increased reticulocyte count, and elevated indirect bilirubin level support the diagnosis of hemolytic anemia. The presence of a low alkaline phosphatase level (copper interferes with the synthesis of alkaline phosphatase enzymes), a moderate elevation of aminotransferase levels despite other evidence of liver dysfunction, and hemolytic anemia make Wilson disease likely. The most common screening test for Wilson disease is serum ceruloplasmin, which is reduced; elevated urine excretion of copper is ascertained to verify the presumptive diagnosis of Wilson disease. In a young patient with elevated liver test results, a low ceruloplasmin level, and elevated urine copper excretion, liver biopsy is typically obtained to confirm the diagnosis of Wilson disease. Liver biopsy demonstrates excessive intrahepatic copper. Kayser-Fleischer rings, noted on ophthalmologic examination, indicate copper deposition in the Descemet membrane of the iris. Patients with acute liver failure due to Wilson disease rarely recover and should be urgently referred for liver transplantation.

Acetaminophen hepatotoxicity and herpes hepatitis present with very high aminotransferase levels, often over 5000 U/L. This patient's aminotransferase levels are not compatible with these conditions.

Budd-Chiari syndrome, characterized by an obstruction of hepatic venous outflow, can occasionally present with acute liver failure but has ascites as a predominant clinical manifestation. This patient does not have ascites, which makes Budd-Chiari syndrome unlikely.