Serum HBsAg levels are associated with the duration of chronic HBV infection and may have a role in predicting the extent of hepatic fibrosis.

In a recent study, investigators evaluated data from the SONIC-B database. This database has data from 8 global randomized trials and two large hepatology centers. Investigators studied the relationship between HBsAg levels and presence of significant fibrosis (Ishak 3-4) or cirrhosis (Ishak 5-6). Clinically relevant cut-offs were identified in order to rule out cirrhosis.

Of the dataset of 2779 patients, 1866 were HBeAg-positive and 322 had cirrhosis. Among HBeAg-positive patients, lower HBsAg levels were found to be linked with higher rates of significant fibrosis and cirrhosis. No relationship could be identified among HBeAg-negative patients. Among HBeAg-positive patients, genotype specific HBsAg cut-offs were shown to have excellent NPVs of >97% and low misclassification rates (≤7.1%). They could therefore be used to rule out cirrhosis. Diagnostic performance of the HBsAg cut-offs was comparable among patients in whom it was not possible to rule out cirrhosis with FIB-4.

To conclude, HBV genotype specific HBsAg cut-offs may be useful in ruling out cirrhosis in HBeAg-positive patients with genotypes B, C and D. They could serve as an adjunct to FIB-4 to limit the need for further testing.

Source: Sonneveld MJ, Hansen BE, Brouwer WP, et al. Hbsag Levels Can Be Used to Rule Out Cirrhosis in Hbeag Positive Chronic Hepatitis B: Results From the Sonic-B Study. J Infect Dis. 2020 Apr 21;jiaa192.