Screening and characterization of HEV infections
A complete range of Anti-Hepatitis E Virus (HEV) ELISAs provides reliable detection of HEV-specific antibodies of classes IgA, IgG and IgM either together for screening purposes or separately for characterizing HEV infections. In regions with a low HEV prevalence the IgAGM ELISA is an economical option for screening patients with a suspected infection. Only positive results need to be followed up with the individual Ig class-specific ELISAs to discriminate between acute and past infections. IgM antibodies indicate an acute infection. IgA testing supplements the IgM determination and increases the reliability of diagnosis. IgA antibodies are to some extent produced earlier in the course of infection than IgM and remain detectable for longer. Moreover, IgA analysis can identify the rare acute cases where specific IgM are not formed. IgG antibodies in the absence of IgM and IgA confirm a past infection. The EUROIMMUN IgG ELISA is the only commercial HEV ELISA to provide quantification in international units (IU/ml). It is calibrated according to the WHO reference serum and shows first-rate linearity with respect to this standard. The microplates of the Anti-HEV IgA, IgG, IgM and IgAGM ELISAs are coated with highly purified recombinant HEV structural proteins, which ensure high sensitivity and specificity in antibody detection. Infections with HEV are the most frequent cause of non-A, non-B hepatitis worldwide. They are generally acquired fecal-orally via contaminated drinking water or food (e.g. insufficiently cooked pork). HEV is endemic primarily in countries with low standards of hygiene, but is also increasingly observed in industrialized nations. HEV infections generally take a mild course, but in rare cases they can lead to acute liver failure. Prognosis is particularly poor in pregnant women, and in this group the mortality rate reaches up to 20%. Since an HEV infection resembles hepatitis A and other hepatides in the preliminary stages, differential diagnostic tests as part of the clinical and laboratory investigation are essential. Alongside PCR analysis of viral RNA in blood or stool, the serological detection of HEV-specific antibodies plays a decisive role in acute HEV diagnostics. The Anti-HEV ELISAs are also suitable for epidemiological studies and, in combination with PCR, for blood donor screening.
