This protocol has been very widely used in our laboratory. The local lab labeling is called \u00ab\u00a0amplification of the R0 region\u00a0\u00bb, However it is clearer to say that the amplicon corresponds to position 912 to 1264 of reference sequence from Kuo et al 1988, excluding the primer sequences. Sens primer is a 22 mer well conserved as locate complementary to the antigenomic ribozyme sequence cleavage site. The sens primer sequence 890->911 is 5\u2019 CAT gCC gAC CCg AAG AGG AAA g 3\u2019. Antisens primer corresponding to the antigenomic sequence 1288->1265: 5\u2019 gAA ggA Agg CCC TCg AgA ACA AgA 3\u2019 which is in the HD gene, corresponding to the sequence of the peptide \u2018RKALENK\u2019 located at the end of the first arginin rich motif.As this amplicon also contains the sequence coding the carboxyterminal extention of L-HDAg, it has been widely used for genotyping although caution should be made: HDV genotyping best relies on the full length S-HDAg gene or the full-length genome sequence.