Analysis of unusual patterns of HBV serologic markers including HBsAG, anti-HBc and anti-HBs

Abstract

Clinical significance of various patterns generated by serologic markers including HBsAg, anti-HBc and anti-HBs is well known. However, some unusual serologic patterns including “anti-HBc alone” and “coexistence of HBsAg and anti-HBs” are difficult to interpret. In this study, patients with “anti-HBc alone” and those with “coexistence of HBsAg and anti-HBs” were categorized and analyzed to evaluate the infection status of patients with unusual serologic patterns.During the 7 years from January 2006 to December 2012, the hepatitis B screening results including concurrent HBsAg, anti-HBc and anti-HBs in Severance Hospital, Yonsei University College of Medicine were reviewed. Among 132,238 patients, “anti-HBc alone” was identified in 10,864 (8.2%) patients and “coexistence of HBsAg and anti-HBs” in 385 (0.3%) patients.Patients with “anti-HBc alone” were classified into 4 categories as follows: 1) patients with past resolved HBV infection with decreased titers of anti-HBs, 1,087/10,864 (10.0%) cases, 2) patients with the ‘‘window period’’ of acute HBV infection, 20/10,864 (0.2%) cases, 3) patients with occult HBV infection with undetectable HBsAg, 406/10,864 (3.7%) cases, and 4) remaining patients unable to categorized, 9,351/10,864 (86.1%) cases.Among 385 patients with “coexistence of HBsAg and anti-HBs”, 23 (6.0%) showed HBsAg disappearance and among those, 19 (4.9%) had seroconversed to anti-HBs positive on follow-up assays.In summary, patients with unusual serologic patterns of HBV markers including “anti-HBc alone” and “coexistence of HBsAg and anti-HBs” were 8.2% and 0.3% of the total requested cases, respectively by current sensitive chemiluminiscent immunoassay. Among cases with “anti-HBc alone”, cases with past resolved HBV infection with decreased titers of anti-HBs were the most frequent (1,087/1,513; 71.8%) with the exception of unclassifiable patients. Within patients with “coexistence of HBsAg and anti-HBs”, positive results of HBsAg were continued in most individuals (111/134; 82.8%) who had follow-up results of HBsAg beyond 6 months from the day with coexistence pattern appeared