title: Comparison of two immunoassays for determining hepatitis B virus serum markers.
abstract: BACKGROUND
  To evaluate and compare the detection efficacy of serum hepatitis B virus (HBV) markers by two immunoassays: electrochemiluminescence immunoassay (ECLIA) and enzyme-linked immunosorbent assay (ELISA).
  
  
  METHODS
  ECLIA and ELISA were used to analyze 359 serum samples, including 64 HBsAg/anti-HBs coexistence serological pattern samples (samples positive for both HBsAg and anti-HBs), 24 HBeAg/anti-HBe coexistence serological pattern samples (samples positive for both HBeAg and anti-HBe), and 271 normal serological pattern samples (negative for either of the combinations).
  
  
  RESULTS
  In the normal serological pattern samples, the concordance rates of the two methods in detecting serum HBV markers were as follows: 97.05% for HBsAg, 92.62% for anti-HBs, 100% for HBeAg, 76.75% for anti-HBe, and 58.67% for anti-HBc. The differences in the qualitative criteria for anti-HBc and anti-HBe were primarily responsible for the discrepancy between the two methods (κ-values of 0.657 and 0.253, respectively). Most weak positive results, determined by ECLIA, were negative determined by ELISA, whereas the results of HBsAg, anti-HBs, and HBeAg detection were generally consistent. In the HBsAg/anti-HBs coexistence serological pattern samples, the concordance rates of HBsAg and anti-HBs detection were 98.44% and 34.38%, respectively. The positive rate of ELISA does not vary as the COI (cut-off index) varies which was determined by ECLIA; in the HBeAg/anti-HBe coexistence serological pattern samples, the concordance rates of HBeAg and anti-HBe detection were 45.83% and 79.17%, respectively. Most weak positive results, determined by ECLIA, were negative when determined by ELISA.
  
  
  CONCLUSIONS
  The discrepancies between the two assays in normal serological patterns samples and HBeAg/anti-HBe coexistence serological pattern samples were mostly due to the different sensitivity of the two assays, but for the HBsAg/anti-HBs coexistence serological pattern samples, the discrepancy was not caused by the different sensitivity. It is the difference in determining anti-HBs which led to the discrepancy.
authors.affiliation: Department of Clinical Laboratory, Renmin Hospital of Wuhan University, Hubei Province, China.
authors.forename: Wanzhou
authors.initials: W
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Ming
authors.initials: M
authors.lastname: Wang
authors.forename: Jian
authors.initials: J
authors.lastname: Gu
mesh_terms: D015415:Biomarkers / Q000097:blood*; D006509:Hepatitis B / Q000097:blood*; D006515:Hepatitis B virus; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers