[HBV-DNA assay by hybridization in solution. Value of low levels measured with the Abbott-Genostics device]

Quantitation of HBV-DNA is the most precise test for measuring viral replication. A commercial liquid phase hybridation test (Abbott) is now commonly used for diagnosis and monitoring of chronic hepatitis B. Interpretation of weak positive results obtained with this test are often difficult. Fifty-four sera with a concentration lower than 12 pg/ml with the Abbott HBV-DNA assay were tested with another commercial hybridation assay (Digene-Murex) and with an in-house PCR test. PCR is positive in 24 sera among the 35 HBs antigen positive sera, but is always negative in HBs Antigene negative sera. All the HBe Antigen positive sera were positive with the PCR test. A positive result was obtained with the Digene test in only 14 sera, 13 of them were confirmed by PCR. Ten sera among the remaining 11 PCR positive sera had a low HBV-DNA concentration but under the Digene cut-off level (10 pg/ml). The sensitivity could be greatly enforced with a lower cut-off level without any lack of specificity. The PCR test remains very helpful for sera with low concentration of HBV-DNA.