title: A collaborative study to establish the 3rd WHO International Standard for hepatitis B virus for nucleic acid amplification techniques.
abstract: Nucleic acid amplification techniques (NAT) are routinely used for clinical diagnostics and monitoring hepatitis B virus (HBV) infections, and are implemented on a voluntary basis for blood screening. A collaborative study was performed to evaluate a replacement WHO International Standard for HBV for the standardization of NAT. Two lyophilised HBV candidates were evaluated by 16 laboratories worldwide, alongside the existing HBV International Standard. The overall mean potency estimates for the candidate samples 1 and 2, relative to sample 3 (2nd HBV International Standard), from quantitative assays, were 5.93 and 5.98 log10International Units (IU)/mL respectively. The variability in individual laboratory mean estimates for samples 1-3 for quantitative assays was ∼0.3 log10IU/mL. The inter-laboratory variability for qualitative assays was higher. Accelerated thermal degradation studies indicate that both lyophilised candidates are stable and suitable for long-term use. Overall, the results suggested that both candidates were suitable as replacement International Standards. Sample 1 (NIBSC code 10/264) was established as the 3rd WHO International Standard for HBV for NAT with an assigned potency of 850,000 IU/mL (∼5.93 log10IU/mL), when reconstituted in 0.5 mL of nuclease-free water. It is intended for the calibration (in IU) of secondary reference materials used in HBV NAT.
authors.affiliation: Division of Virology, NIBSC, Medicines and Healthcare Products Regulatory Agency, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK. Electronic address: Jacqueline.Fryer@nibsc.org.
authors.forename: Jacqueline F
authors.initials: JF
authors.lastname: Fryer
authors.affiliation: Biostatistics, NIBSC, Medicines and Healthcare Products Regulatory Agency, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK.
authors.forename: Alan B
authors.initials: AB
authors.lastname: Heath
authors.affiliation: Division of Virology, NIBSC, Medicines and Healthcare Products Regulatory Agency, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK.
authors.forename: Dianna E
authors.initials: DE
authors.lastname: Wilkinson
authors.affiliation: Division of Virology, NIBSC, Medicines and Healthcare Products Regulatory Agency, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK.
authors.forename: Philip D
authors.initials: PD
authors.lastname: Minor
mesh_terms: D004279:DNA, Viral / Q000235:genetics*; D005612:Freeze Drying; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D007391:International Cooperation; D021141:Nucleic Acid Amplification Techniques / Q000379:methods* / Q000592:standards*; D012015:Reference Standards; D015203:Reproducibility of Results; D014944:World Health Organization
chemical_list: D004279:DNA, Viral
keywords: HBV; Hepatitis B; International standard; NAT; Standardization