Comparison of real-time RT-PCR assays for hepatitis E virus RNA detection.

BACKGROUND

Hepatitis E virus (HEV) is an increasing cause of acute viral hepatitis in developed countries. Serological testing alone may fail to diagnose acute infection, especially in immunocompromised patients, which justifies the use of molecular assays for diagnosis. Few studies have compared accuracy of HEV RNA detection assays.

OBJECTIVES

The performances of five real-time PCR procedures for HEV RNA detection were compared.

STUDY

DESIGN

First, RNA quantification of hepatitis E diluted standards of 3a and 3b genotypes were performed. Secondly, forty-seven clinical samples of patients with known acute HEV infection were tested using five hepatitis E RNA detection methods of assigned letters A, B, C, D and E.

RESULTS

Standards of HEV 3a genotype were detected in 100% of replicates with 2500 UI/ml of sensitivity by using A, B and C assays. Standards of HEV 3b genotype were more accurately detected with a sensitivity of 25 UI/ml in 100% of replicates using C assay and were detected in 100% of replicates with 2500 UI/ml of sensitivity by using A, B and E assays. Overall, B assay detected all of 250 UI/ml dilution and occasionally the 25 UI/ml dilution on both subtypes. The detection rates of clinical samples were 100%, 100% 97%, 97% and 83% for the respective A, B, C, D and E assay. Assays A and B were well correlated, independently of the subtype. However, discrepancies were observed when these techniques were compared to C, D and E assays according to the different subtypes.

CONCLUSION

A and B assays appear reliable for HEV RNA detection. These assays target the ORF2/3 overlapping region, described as more conserved than ORF2.