A fully automated system using transcription-mediated amplification for the molecular diagnosis of hepatitis E virus in human blood and faeces.

BACKGROUND AND OBJECTIVES

We evaluated the performance of the Procleix HEV RNA assay implemented on the Panther automated platform for detecting HEV RNA.

STUDY DESIGN AND RESULTS

Analytical specificity was 100% and there was no cross contamination, as assessed by assaying 122 plasma samples from HEV RNA-negative blood donors. The limits of detection were determined by Probit analysis with the WHO HEV standard (HEV subtype 3a) and subtype 3f and 3c reference strains. The limit of detection was 24 [CI 95%: 19-33] IU/ml for subtype 3a, 34 [28-44] IU/ml for subtype 3c and 53 [41-76] IU/ml for subtype 3f. Inclusivity was assessed by testing 91 samples: HEV genotype 3 subtypes 3c (n = 29), 3e (n = 8), 3f (n = 50), genotype 4 (n = 3), and genotype 1 (n = 1). All the samples tested positive. Clinical performance was determined by testing prospectively 500 consecutive plasma samples and 19 faecal samples with the Procleix assay and a reference accredited quantitative RT-PCR assay. The assays were concordant for 492/500 plasma samples (98.4%) and 18/19 (94.7%) fecal samples. We also tested 92 IgM-positive/HEV RNA-negative samples with the reference assay. The IgM-positive samples included 43 (46%) that tested negative with the reference RT-PCR assay and positive with the Procleix HEV assay.

CONCLUSIONS

The Procleix HEV assay performed well and appears to be suitable for molecular diagnosis of HEV infection, monitoring HEV infections, and facilitating epidemiological investigations.