Sustained false-positive results for hepatitis A virus immunoglobulin M: A case report and literature review

Hepatitis A virus immunoglobulin M (HAV-IgM) is often used to diagnose acute hepatitis A virus (HAV) infection serologically. However, false-positive test results can interfere with the diagnosis. A 56-year-old woman was readmitted to the hospital owing to abnormal liver function tests for the last 18 months. She had been diagnosed with acute HAV and was hospitalized in isolation based on a positive HAV-IgM test 18 months ago. Regular follow-up after discharge showed abnormal liver function and an elevated level of antinuclear antibodies and immunoglobulin G. For the last 15 days, the patient had fatigue, decreased appetite, and yellow urine, signaling recrudescence. Liver function tests were also abnormal. Liver biopsy revealed histological changes consistent with typical autoimmune hepatitis. After 2 months of methylprednisolone treatment, liver function returned to normal, and HAV-IgM turned negative. The diagnosis of acute HAV in nonendemic areas requires a comprehensive analysis of epidemic history, clinical characteristics, etiology, etc.