Evaluation of two RNA extraction methods for human Parechovirus detection on pediatric stool specimens

BACKGROUND: Human Parechovirus (HPeVs), along with human enteroviruses is associated with gastrointestinal and respiratory infections. The aim of this study was to assess the performance characteristics of two nucleic acid extraction for HPeV-RNA quantitation, the RNAlev Extraction Kit associated with Maxwell automated nucleic acid extractor (Promega, Milan, Italy) and RNAzol manually protocol. METHODS: A total of 137 fecal specimens previously routinely screened for Rotavirus and Adenovirus were tested for HPeV virus. RESULTS: Methods 1 and 2 detected HPeV-RNA in 11 and 10 samples, respectively, with a 96.2% concordance. In particular. 124/137 (90.5%) were concordantly negative by both methods: 81137 (5.8%) concordantly positive. For the 8 specimens that were positive by both tests, the population mean (SD) was 320 (601) copies/mg with method 1 and 1216 (2338) copies/mg with method 2. By referring to the 8 specimens that were concordantly positive, the correlation value between the two methods was not statistically significant (r=0.381 and P=0.3599). Bland-Altman analysis showed that differences between the two methods were within +/- 1000 copies/mg of the averaged results for all of the tested specimens. CONCLUSIONS: Method 2, being a semi-automated method, provides benefits over a manual method, in terms of turn-around time, less errors and reliability.