An international collaborative study to establish a World Health Organization international standard for hepatitis B virus DNA nucleic acid amplification techniques

Saldanha, J.; Gerlich, Wolfram H.; Lelie, Nico; Dawson, Peter J.; Heermann, Klaus-Hinrich; Heath, Alan

doi:10.1046/j.1423-0410.2001.00003.x

Cited by 234 publications

(169 citation statements)

References 15 publications

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“…Tenfold, serially diluted HBV DNAs ranging from 2.4 ϫ 10 1 to 2.4 ϫ 10 10 IU/mL were used to generate a standard curve for each reaction. One IU/mL was converted into 5 copies/mL according to Saldanha et al 20 The concentrations of HBV DNA in clinical specimens were calculated using the standard curve equation: Ct ϭ slope ϫ log copy ϩ intercept. The dynamic range of detection was found to be 366Ϸ3.66 ϫ 10 11 copies/mL (r 2 ϭ 0.998).…”

Section: Methodsmentioning

confidence: 99%

Increased risk of adefovir resistance in patients with lamivudine‐resistant chronic hepatitis B after 48 weeks of adefovir dipivoxil monotherapy†

et al. 2006

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Although adefovir dipivoxil (ADV) has a unique profile of delayed and infrequent resistance in treatment-naïve chronic hepatitis B patients, the association of ADV resistance with previous lamivudine (LAM) resistance is not well understood. We compared the emergence of the ADV-resistant mutations rtA181V/T and rtN236T between LAM-resistant patients and treatment-naïve patients at 48 weeks of ADV monotherapy. Fifty-seven LAM-resistant patients and 38 treatment-naïve patients were treated with 10 mg/d ADV for more than 48 weeks. Both baseline and 48-week blood samples were analyzed for ADV-resistant mutations via restriction fragment mass polymorphism analysis. Antiviral responses were evaluated according to changes in serum HBV DNA (measured via real-time polymerase chain reaction) and alanine aminotransferase (ALT) levels and loss of hepatitis B e antigen (HBeAg). After 48 weeks, 10 (18%) of the 57 LAM-resistant patients were found to have developed ADV-resistant mutations, whereas none of the 38 treatment-naïve patients developed such mutations (P < .01). Among LAM-resistant patients, the reduction in serum HBV DNA levels was significantly lower in patients with ADV-resistant mutations than in those without such mutations (؊1.04 vs. ؊2.63 log 10 copies/mL) (P ‫؍‬ .01). However, the rates of serum ALT normalization (60% vs. 55%) and HBeAg loss (14% vs. 21%) were not significantly different between the 2 groups (P > .05). In conclusion, the emergence of the rtA181V/T and rtN236T mutations was more common in LAM-resistant patients than in treatmentnaïve patients after 48 weeks of ADV therapy and was associated with reduced antiviral efficacy to drug treatment. (HEPATOLOGY 2006;43:1385-1391

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Section: Methodsmentioning

confidence: 99%

Increased risk of adefovir resistance in patients with lamivudine‐resistant chronic hepatitis B after 48 weeks of adefovir dipivoxil monotherapy†

et al. 2006

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“…Viral load was determined by using either the Digene Hybrid Capture System (Digene) in copies ml 21 , the Versant HBV bDNA Assay (Siemens Healthcare Diagnostics) in copies ml 21 or the Cobas TaqMan Assay (Roche Molecular Systems) in IU ml 21 . The approximate conversion factor for copies ml 21 to IU ml 21 is 5 (Saldanha et al, 2001). …”

mentioning

confidence: 99%

Hepatitis B virus genotype G epidemiology and co-infection with genotype A in Canada

Osiowy

Gordon²,

Borlang³

et al. 2008

Journal of General Virology

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Hepatitis B virus (HBV) genotype G (HBV/G) is an unusual variant, and little is known about its epidemiology and natural history, particularly the requirement for a co-infecting HBV genotype and their relationship during infection. This study investigated the quasispecies nature of coinfecting genotypes in 39 samples collected over a 6 year period from 13 HBV/G-infected patients. HBV/G infections were found to occur predominantly in males (92 %) and were primarily associated with male homosexual sex (67 %). All patients were infected with HBV/G and HBV/A, or a recombinant HBV/A/G strain. Co-infecting genotypic prevalence was often observed to fluctuate over time, with periods of HBV/G monoinfection in some patients. The average sequence divergence among Canadian HBV/G strains was 1.57±0.62 %. Thus, all HBV/G infections in Canada occur in the context of co-infection or recombination with HBV/A, and strains display increased sequence divergence compared with all known HBV/G sequences described to date.

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“…Realtime PCR assays have become more widely available and preferred in the initial evaluation of patients, and even, more importantly in the monitoring of both treated and untreated patients. The current lack of standardization between assays, which make it difficult to compare data from different laboratories will be resolved with the introduction of an HBV-DNA standard (Saldanha et al, 2001). In the future all results should be reported in IU/ml (IU/ml equals approximately 5.6 genome/ml) (Keeffe et al, 2006).…”

Section: Estimation Of Hbv By Elisa Testmentioning

confidence: 99%

Comparative Assessment between Serological and Molecular Diagnosis for Patients Groups with Hepatitis B Virus

Radii¹,

Saud²

2017

Int.J.Curr.Microbiol.App.Sci

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An international collaborative study to establish a World Health Organization international standard for hepatitis B virus DNA nucleic acid amplification techniques

Abstract: The titres (genome equivalents/ml) of three HBV preparations were determined by several laboratories using different NAT assays. This study enabled the establishment of an international standard, 97/746, for HBV DNA NAT assays.

Cited by 234 publications

References 15 publications

Increased risk of adefovir resistance in patients with lamivudine‐resistant chronic hepatitis B after 48 weeks of adefovir dipivoxil monotherapy†

Increased risk of adefovir resistance in patients with lamivudine‐resistant chronic hepatitis B after 48 weeks of adefovir dipivoxil monotherapy†

Hepatitis B virus genotype G epidemiology and co-infection with genotype A in Canada

Comparative Assessment between Serological and Molecular Diagnosis for Patients Groups with Hepatitis B Virus

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