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Volume 19, Number 5—May 2013
Research

World Health Organization International Standard to Harmonize Assays for Detection of Hepatitis E Virus RNA

Sally A. BaylisComments to Author , Johannes Blümel, Saeko Mizusawa, Keiji Matsubayashi, Hidekatsu Sakata, Yoshiaki Okada, C. Micha Nübling, Kay-Martin O. Hanschmann, and the HEV Collaborative Study Group
Author affiliations: Paul-Ehrlich-Institut, Langen, Germany (S.A. Baylis, J. Blümel, C.M. Nübling, K.-M.O. Hanschmann); National Institute of Infectious Diseases, Tokyo, Japan (S. Mizusawa, Y. Okada); Japanese Red Cross Hokkaido Block Blood Center, Sapporo, Japan (K. Matsubayashi, H. Sakata)

Main Article

Table 3

Overall mean potencies of samples 2, 3, and 4 relative to sample 1 from quantitative and qualitative analysis of HEV samples in study to establish a WHO International Standard for HEV RNA NAT-based assays*

Sample and assay type No. Mean (95% CI)† SD % CV
Sample 2
Quantitative 19 5.46 (5.35–5.58) 0.23 3
Qualitative 13 5.42 (5.38–5.46) 0.07 1
Combined
 32
 5.45 (5.38–5.51)
 0.18
 2
Sample 3
Quantitative 20 5.45 (5.27–5.65) 0.43 5
Qualitative 13 5.48 (5.37–5.59) 0.18 2
Combined
 33
 5.46 (5.35–5.58)
 0.35
 4
Sample 4
Quantitative 20 5.51 (5.38–5.64) 0.29 3
Qualitative 13 5.47 (5.36–5.59) 0.19 2
Combined 33 5.49 (5.41–5.58) 0.25 3

*Mean potency values were determined by assigning a value of 5.39 log10 units/mL for sample 1. Samples 1 and 2, replicate samples of the candidate WHO International Standard; samples 3 and 4, replicate samples of the candidate Japanese national standard. HEV, hepatitis E virus; WHO, World Health Organization; NAT, nucleic acid amplification technique; no., no. dilutions analyzed (in linear range for quantitative assays); % CV, geometric coefficient of variation.
†Values are log10 copies/mL for quantitative and log10 NAT technique–detectable units/mL for qualitative assays.

Main Article

1Members of the HEV Collaborative Study Group are listed at the end of this article.

2In memory of Thomas Laue.

Page created: April 01, 2013
Page updated: April 01, 2013
Page reviewed: April 01, 2013
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