ABSTRACT
Recent clinical studies suggest that hepatitis B virus (HBV) load and genotype may be independent predictors of responses to antiviral therapies. However, it is difficult for clinicians to accurately determine viral loads in patient samples because results--both the values and the units of measure--can vary greatly among different tests. Accordingly, the World Health Organization (WHO) has produced the first international standard for HBV DNA for nucleic acid amplification technology (NAT) assays. In the present study, we describe the performance of the target-capture PCR HBV DNA quantitative assay for the quantitation of HBV DNA in clinical samples and reference panels. The range of quantitation was between 50 and 10(10) IU/ml. The sensitivity and accuracy of the target-capture PCR assay were demonstrated by using the HBV panel from Quality Control for Medical Diagnostics (QCMD) and the WHO HBV DNA standard. The target-capture PCR assay quantitated the six genotype A members of the QCMD panel and dilutions of the WHO HBV DNA standard within an accuracy of 74 to 142%. Compared to current serological methods, the assay offers window period reductions of 19 days prior to HBV surface antigen and 26 days prior to HBV e antigen detection. The target-capture PCR assay was also compared with four commercially available NAT assays, and the various units of measure were standardized with respect to the international units of the WHO HBV DNA standard. The target-capture PCR assay is a sensitive, accurate, high-throughput, rapid, and reproducible assay for the determination of HBV loads.
Subject(s)
DNA, Viral/analysis , Hepatitis B/virology , Polymerase Chain Reaction/methods , Polymerase Chain Reaction/standards , Hepatitis B virus , Humans , Reagent Kits, Diagnostic , Reference Standards , Reproducibility of Results , Sensitivity and Specificity , Viral LoadABSTRACT
Nucleic-acid amplification technology (NAT) assays have been implemented for HCV and HIV-1 in the United States, and many parts of Europe, Australia and Asia. Nucleic acid detection assays utilize many different technologies, and the WHO International Standards for nucleic acid tests are widely used to compare them. Currently, several laboratories are developing an assay for simultaneous detection of HCV RNA, HIV-1 RNA and HBV DNA. In the course of such development it was observed that the WHO International Standard for HIV-1 RNA (97/656) was positive for HBV DNA. In this report we confirm the presence of HBV DNA in the HIV-1 international standard through the qualitative Procleix-Ultrio assay. Further, using the TaqMan technology, through quantitative Bead Capture-TaqMan assay, we report that approximately 1000IU/ml dilution of HIV RNA contains approximately 4500IU/ml of HBV DNA.
