OBJECTIVE: To assess a sensitive and specific technique for detecting serum HBV DNA with an HBVDNA probe labelled directly by alkaline phosphatase (AlkPhos Direc probe).METHODS: AlkPhos Direc probe was prepared with purified HBV DNA labelled directly by alkalinephosphatase. The probe, and chemiluminescent substrate CDP-star for AP were used in hybridizationassay. HBV DNA was detected by autoradiography on a film. The results of 80 samples were comparedbetween the chemiluminescent dot blot hybridization assay with the AlkPhos Direc probe and another assaywith the digoxigenin-labelled HBV DNA probe. The correlation of seventy-sample results of fluorescentquantitative HBV DNA PCR assay and dot blot hybridization assay with the AlkPhos Direc probe wasanalysed.RESULTS: The sensitivity of the AlkPhos Direc probe was 10 pg at least. The coincidence of theAlkPhos Direc probe was 100% compared with that of the digoxigenin-labelled HBV DNA probe. Acorrelation coefficient of HBV DNA quantitative results between fluorescent quantitative HBV DNA PCRassay and dot blot hybridization assay with the AlkPhos Direc probe was 0.98 (P<0.01).CONCLUSIONS: The method detecting HBV DNA in serum with the HBV DNA AlkPhos Direc probe issensitive and specific. The results of the two assays with the AlkPhos Direc probe or with thedigoxigenin-labelled HBV DNA probe are completely coincident. The correlation of HBV DNAquantitative results between fluorescent QPCR assay and dot blot hybridization assay with the AlkPhosDirec probe is satisfactory. OBJECTIVE: To assess a sensitive and specific technique for detecting serum HBV DNA with an HBVDNA probe labeled directly by alkaline phosphatase (AlkPhos Direc probe) .METHODS: AlkPhos Direc probe was prepared with purified HBV DNA labeled directly by alkaline phosphatase. The probe, and chemiluminescent The results of 80 samples were compared between the chemiluminescent dot blot hybridization assay with the AlkPhos Direc probe and another assay with the digoxigenin-labeled HBV DNA probe. The correlation of seventy-sample results of fluorescent quantitative HBV DNA PCR assay and dot blot hybridization assay with the AlkPhos Direc probe was analyzed. RESULTS: The sensitivity of the AlkPhos Direc probe was 10 pg at least. The coincidence of the AlkPhos Direc probe was 100% more with that of the digoxigenin-labeled HBV DNA probe. Acorrelation coefficient of HBV DNA quantitative results between fluorescent quantitative HBV DNA PCRassay and dot blot hybridization assay with the AlkPhos Direc probe was 0.98 (P <0.01) .CONCLUSIONS: The method Detecting HBV DNA in serum with the HBV DNA AlkPhos Direc probe is sensitive and specific. The results of the two assays with the AlkPhos Direc probe or with thedigoxigenin-labeled HBV DNA probes are completely coincident. The correlation of HBV DNAquantitative results between fluorescent QPCR assay and dot blot hybridization assay with the AlkPhosDirec probe is satisfactory.