Application of serologic assays for diagnosing acute hepatitis E in national surveillance of a nonendemic area.

Variant performance of immunoglobulin M (IgM) and immunoglobulin G (IgG) hepatitis E virus (HEV) assays may impact the diagnosis. The present study aimed to evaluate four different IgM/IgG assays for HEV infection for application in national surveillance in nonendemic areas. Sera from 300 patients that were stored in the Centers for Disease Control (CDC) of Taiwan for suspected acute HEV infection from 2004 to 2008, and 18 serum samples from acute cases of HEV infection in Taipei Veteran General Hospital were evaluated. Performances of EIAgen HEV IgG/M (Adaltis, Bologna, Italy), recomWell HEV IgG/M (Mikrogen, Neuried, Germany), MP HEV IgG/M (MP Biomedicals, Singapore), and in-house kits, HEVLPs (HEV virus-like particles) IgG/M were compared. Positive results of serum RNA detected by reverse transcription-polymerase chain reaction were defined as the definite diagnosis. There were five genotype 1, one genotype 3, and nine genotype 4 HEV samples. The four different IgM/IgG assays had excellent performance in terms of negative predictive value (98.4-100%) and varying performance in relation to sensitivity (66.7-93.3%) and specificity (62.9-95.6%). RecomWell IgM had the best overall performance. In addition, the combination of anti-HEV IgM ELISA with anti-HEV IgG or another anti-HEV IgM ELISA provided better screening performance, especially the recomWell IgM and HEVLPs IgM combination (area under the receiver operating curve: 0.94; sensitivity: 100%, specificity 88.1%). In conclusion, anti-HEV IgM ELISA is a good screening test for the national surveillance of acute HEV infection in nonendemic areas and not limited by inconsistent performances of sensitivity and specificity among different assays.