title: Correlation between two chemiluminescence based assays for quantification of hepatitis B surface antigen in patients with chronic hepatitis B infection.
abstract: OBJECTIVE
  Hepatitis B surface Antigen (HBsAg) is the hallmark in diagnosing hepatitis B virus (HBV) infection. In India many commercial assays are available for detection of HBsAg but very few can measure it quantitatively. The present study presents the comparative evaluation of two methods and their correlation with serum HBsAg in chronic hepatitis B (CHB) patients.
  
  
  METHODS
  Consecutive patients of CHB were included and there HBsAg levels were measured by two methods: (i) Elecsys, Roche Diagnostics, a qualitative assay and (ii) Architect, Abbott Diagnostics, a quantitative assay. The HBV DNA was measured by real-time polymerase chain reaction (qPCR).
  
  
  RESULTS
  Total of 136 patients were included in the study and there was a significant overall correlation between both the assays (correlation coefficient [r] = 0.83; P < 0.001). Assays correlated well with each other across all subgroups of CHB: treatment naοve (r = 0.73; P < 0.001, n = 32), on treatment (r = 0.56; P < 0.05, n = 104), hepatitis Be (HBe) antigen positive (r = 0.67; P < 0.001, n = 62) and anti-HBe positive (r = 0.61; P < 0.05, n = 74) group. On correlation with serum HBV DNA, Architect assay demonstrated good correlation (r = 0.73; P < 0.001, n = 136) as compared to the Elecsys assay (r = 0.27; P = 0.068, n = 136). Architect HBsAg QT assay (A1) also correlated well with HBV DNA in the treatment naοve group (r = 0.69; P < 0.001, n = 32).
  
  
  CONCLUSIONS
  Our study hence proved that both the assays are comparable and a simple qualitative assay with in-house modification can be used easily for quatitation of HBsAg in clinical samples.
authors.affiliation: Department of Virology , Institute of Liver and Biliary Sciences, Vasant Kunj, New Delhi, India.
authors.forename: E
authors.initials: E
authors.lastname: Gupta
authors.forename: P
authors.initials: P
authors.lastname: Pandey
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: M K
authors.initials: MK
authors.lastname: Sharma
authors.forename: S K
authors.initials: SK
authors.lastname: Sarin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000097:blood; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D019694:Hepatitis B, Chronic / Q000175:diagnosis*; D006801:Humans; D007194:India; D008163:Luminescent Measurements / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens