Comparison of two methods for quantification of hepatitis B viral DNA

Background: Quantitation of serum hepatitis B virus (HBV) DNA has proven us eful in assisting with patient management and treatment and several commerc ially available assays have been developed to quantify serum HBV-DNA levels . Methods: The performance of the cross-linking assay and the branched-DNA si gnal amplification (bDNA) assay for the quantitative measurement of HBV-DNA was studied in 99 hepatitis B surface antigen-positive and viraemic patien ts. Results: Of these samples, 82 (83%) were positive for HBV-DNA by both assay s and four (4%) were below the cut-off for bath assays. Of the remaining 13 samples, 10 contained measurable levels of HBV-DNA by the cross-linking as say alone and three other samples contained measurable levels of HBV-DNA by the bDNA assay alone. The sensitivity gain of the cross-linking assay rela tive to bDNA assay in this study population was 10/92 (11%). In addition, a linear regression analysis showed that the HBV-DNA levels obtained from bo th assays was significantly correlated (gamma = 0.974, P < 0.0001). Conclusions: These findings suggest that the recently developed cross-linki ng assay is more sensitive than the bDNA assay for the quantitative determi nation of HBV-DNA. (C) 1999 Blackwell Science Asia Pty Ltd.