Table 3 Primer sequences used for HBV genotyping by nested PCR (position, specificity, and polarity). An "M " represents a nucleotide that could be either an A or a C; a "Y" represents a nucleotide that could be either a C or a T. nt, nucleotide.

Step-one PCR

P1b universal, sense)

5'-TCA CCA TAT TCT TGG GAA CAA GA-3'

nt2823-2845,

1065 bp

S1-2 universal, antisense)

5'-CGA ACC ACT GAA CAA ATG GC-3'

nt685-704,

Step-two PCR

B2 sense

5'-GGC TCM AGT TCM GGA ACA GT-3'

nt67-86, types A specific, to E

Mix A

BAIR antisense

5'-CTC GCG GAG ATT GAC GAG ATG T-3'

nt113-134, type A specific,

68 bp

BBIR antisense

5'-CAG GTT GGT GAG TGA CTG GAG A-3'

nt324-345, type B specific,

122 bp

BCIR antisense)

5'-GGT CCT AGG AAT CCT GAT GTT G-3'

nt165-186, type C specific,

281 bp