Serum hepatitis B core-related antigen is more accurate than hepatitis B surface antigen to identify inactive carriers, regardless of hepatitis B virus genotype

Objectives: To investigate whether hepatitis B surface antigen (HBsAg) and hepatitis B core-related antigen (HBcrAg) levels are useful to identify inactive carriers among HBeAg-negative patients infected by different hepatitis B virus (HBV) genotypes. Methods: In all, 202 consecutive HBeAg-negative patients with chronic hepatitis B, 135 inactive carriers and 67 with HBV activity, were prospectively followed for 1 year. Results: In HBeAg-negative patients, HBsAg levels differed across the different genotypes (p < 0.001). The highest levels were observed in genotypes F or H (4.2 +/- 0.6 logIU/mL), followed by genotype E (3.4 +/- 1.1 logIU/mL), genotype A (3.4 +/- 0.8 logIU/mL), and the lowest in genotype D (2.7 +/- 1.1 logIU/mL). Variations in HBsAg levels were similar in inactive carriers and patients with HBV activity. HBsAg < 3 logIU/mL showed good performance for identifying genotype D inactive carriers: 76% of genotype D inactive carriers met this cut-off versus <= 31% for genotypes A, E, F or H. However, in patients with genotype A, HBsAg levels <= 3.7 logIU/mL better classified inactive carriers. The combination of a single measurement of HBcrAg <= 3 logU/mL plus HBV DNA <= 2000 IU/mL yielded a positive predictive value and diagnostic accuracy > 85% in all HBV genotypes, except genotype H or F, with values of 62.5% and 72.7%, respectively, for the two parameters. Conclusions: HBsAg levels varied across genotypes in HBeAg-negative patients. HBsAg levels < 3 logIU/mL were only useful for identifying genotype D inactive carriers. A single HBcrAg measurement <= 3 logU/mL plus HBV DNA <= 2000 IU/mL was highly accurate for identifying inactive carriers, regardless of their HBV genotype. (C) 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.