Diagnosis

The commonly used tests for HEV infection are IgM and IgG anti-HEV antibody assays and molecular assays. HEV IgM antibodies appear early (from 1-4 weeks) in the course of illness and disappear over 4–5 months. Assays detecting anti-HEV are usually qualitative sandwich immunoassays developed with recombinant HEV antigens that provide a broad coverage of all 4 major HEV genotypes. The antigens typically represent part of the ORF2 and ORF3 proteins and studies have shown that assays based on open reading frame 2 (ORF2) can be more sensitive than those based on ORF3. Simultaneous assessment of anti-HEV IgA has been recommended to improve specificity as the IgM assay may cross-react with other IgM-based assays such as rheumatoid factor IgM. Overall recombinant protein-based tests have demonstrated an ability to detect anti-HEV in 90 to 95% of symptomatic HEV cases.