Patients with HBeAg negative chronic HBV and evidence of hepatic disease (elevated liver enzymes or evidence of cirrhosis) who have significant viremia are treated with anti HBV therapy. Currently the key goals of anti HBV therapy are profound and prolonged viral suppression and treatment efficacy is assessed by monitoring viral load and liver enzymes. However these do not always reflect the degree of liver impairment or the degree of improvement in response to therapy. Sebivo has been accepted in Israel as a first line therapy for HBeAg negative and HBeAg positive chronic HBV with evidence of liver damage. Viral load should decrease by 1 log every 3 months, otherwise patients should be offered add-on or alternative therapy. As the majority of patients in Israel are HBeAg negative chronic HBV and in order to have homogenous population we will select for our study only patients with HBeAg negative chronic HBV. The 13C Methacetin breath test, assess liver function and specifically the function of the microsomal CYP4501A2. It has been shown to correlate with the degree of liver impairment and with clinical outcomes in both acute and chronic liver disease. The aim of this study is to determine the utility of the 13C Methacetin Breath Test to follow up patients with HBeAg negative chronic HBV receiving anti viral therapy.