I thank Dr Linghua and Dr Xinguang1 for their interest in my recent Review (Diagnosis of hepatitis E. Nat. Rev. Gastroenterol. Hepatol. doi:10.1038/nrgastro.2012.187).2

Their query relates to assays for detection of 'chronic carriage' of hepatitis E virus (HEV). Antibody assays are not useful for this purpose. In addition, tests for detection of HEV antigen are unlikely to be sufficiently sensitive to detect small amounts of virus. Hence, tests for detection of HEV RNA are needed.

The experience with loop-mediated isothermal amplification (LAMP) assay for detection of HEV RNA is quite limited. As the Review indicates, the ability of this assay to detect all HEV genotypes has not been assessed. Furthermore, I believe that any positive results with these assays in new settings, such as in the studies proposed by Linghua and Xinguang, would need confirmation using assays based on PCR, which are much better established than LAMP.