Quantification of HBsAg: Basic virology for clinical practice

Table 2 Mutations in viral polymerase gene induced by oral antiviral agents and corresponding changes in hepatitis B surface antigen

Polymerase domain	Mutation in polymerase	Oral antiviral agents	Corresponding change in HBsAg
B	rtI169T	ETV	sF161H/L
	rtL180M	LAM, LdT	No change
	rtA181T	ADV, TFV, LAM, LdT	sW1721
	rtA181T	ADV, TFV, LAM, LdT	sW172L
	rtA181V	ADV, TFV, LdT	sL173F
	rtT184A	ETV	No change
	rtT184C	ETV	sL175F + sL176V
	rtT184I	ETV	No change
	rtT184G	ETV	sL176V
	rtT184S	ETV	sL175F
	rtT184M	ETV	sL1761
	rtT184L	ETV	sL175F
C	rtS202C	ETV	No change/sS193F
	rtS202I	ETV	sV194F/S
	rtS202G	ETV	No change/sS193L
	rtM204V	LAM	sI195M
	rtM204I	LAM, LdT	sW1961/S/L
D	rtN236T	ADV, TFV	After end of HBsAg
E	rtM250I	ETV	After end of HBsAg
	rtM250V	ETV	After end of HBsAg

¹Stop codon. Modified from reference[50]. HBsAg: Hepatitis B surface antigen; ETV: Entecavir; LAM: Lamivudine; LdT: Telbivudine; ADV: Adefovir; TFV: Tenofovir.