title: HBsAg level and hepatitis B viral load correlation with focus on pregnancy.
abstract: BACKGROUND
  Viral load measurement is necessary to estimate mother-to-child transmission risk for women with chronic hepatitis B (CHB), however, it is expensive. The present study aimed to investigate the relationship between HBsAg and hepatitis B virus (HBV) DNA levels, and to determine potential applications of HBsAg level monitoring for estimating viral load.
  
  
  METHODS
  85 patients with CHB (31 pregnant women, 26 non-pregnant women, 28 men) were included in the study. HBV DNA level was measured by real-time PCR, and HBsAg level by chemiluminescent immunoassay method. Dependency between viral load and HBsAg level was determined by Spearman correlation coefficient ρ.
  
  
  RESULTS
  The correlation between HBsAg and HBV DNA levels was significant for all patients [ρ=0.3762 (P<0.0005; n=85)]. In the group of pregnant women, a low (unmeasurable) HBV DNA level led to a decrease in the Spearman coefficient ρ. In almost all cases a low level of the HBsAg corresponded to a low HBV DNA level. Only 2 patients had a low level of HBsAg and a relatively high viral load. By contrast, a high HBsAg level was observed in patients both with high and low viral load.
  
  
  CONCLUSIONS
  Correlation between HBsAg and HBV DNA levels is significant. In most cases, a low level of HBsAg indicates a low HBV DNA level, whereas a high HBsAg level does not always correspond to a high viral load. The measurement of HBV DNA level is necessary for pregnant women with a high HBsAg level.
authors.affiliation: Botkin Infectious Diseases Hospital, St. Petersburg, Russia (Maria Belopolskaya, Sergey Firsov).
authors.forename: Maria
authors.initials: M
authors.lastname: Belopolskaya
authors.affiliation: Institute of System Theory, University of Stuttgart, Stuttgart, Germany (Viktor Avrutin).
authors.forename: Viktor
authors.initials: V
authors.lastname: Avrutin
authors.affiliation: Botkin Infectious Diseases Hospital, St. Petersburg, Russia (Maria Belopolskaya, Sergey Firsov).
authors.forename: Sergey
authors.initials: S
authors.lastname: Firsov
authors.affiliation: St. Petersburg State University, St. Petersburg, Russia (Alexey Yakovlev).
authors.forename: Alexey
authors.initials: A
authors.lastname: Yakovlev
keywords: Hepatitis B; level of HBsAg; pregnancy; viral load