Performance of a commercial assay for detecting and quantifying HEV RNA in faeces

BACKGROUND: Detecting hepatitis E virus (HEV) RNA in faeces is useful for diagnosing and monitoring HEV infections, particularly in immunocompromised patients requiring ribavirin therapy. OBJECTIVES: This study evaluated the performance of the Altona RealStar HEV RNA kit for detecting and quantifying HEV in faeces. STUDY DESIGN: RNA was extracted from 94 stool samples by two methods: QIAamp Viral RNA Mini kit and MagNA Pure 96 automate. The Altona results were compared to a reference laboratory-developed accredited ISO15189 RT-PCR assay. RESULTS: The Altona and reference assays detect HEV RNA in 77/93 (82.8%) and 83/93 (89.2%) of the QIAamp extracted samples, respectively, after exclusion of invalid result; they detected HEV RNA in 67/92 (72.8%) and 66/92 (71.7%) of the MagNA Pure extracted samples, respectively, which emphasizes the importance of the RNA extraction method. The HEV RNA concentrations obtained with Altona RT-PCR and the reference RT-PCR were well correlated whatever the extraction method, and Bland Altman analyses indicated that the Altona values were higher than the reference assay values. The Altona values for QIAamp-extracted and MagNA Pure-extracted HEV RNA were very similar. CONCLUSIONS: The Altona RealStar assay is suitable for quantifying HEV RNA in the faeces and monitoring HEV RNA shedding during ribavirin therapy. Extraction is critical for detecting faecal HEV with high performance RT-PCR assays.