title: Quantitative measurement of serum hepatitis B surface antigen using an immunoradiometric assay in chronic hepatitis B.
abstract: OBJECTIVE
  Measurement of serum hepatitis B virus surface antigen (HBsAg) levels is important for the management of chronic hepatitis B patients in terms of monitoring response to antiviral therapy. This study aimed to evaluate the diagnostic performance of a new diagnostic kit, which quantitatively measures serum HBsAg level using an immunoradiometric assay (IRMA)-based method. Measurements were compared with those obtained using a chemiluminescent microparticle immunoassay (CMIA)-based method.
  
  
  METHODS
  The blood samples of 96 patients with chronic hepatitis B were used in this study. Copy numbers of serum hepatitis B virus (HBV) DNA were determined in 23 of these samples. The correlation between and the concordance of IRMA and CMIA results were determined using Pearson's correlation coefficients. P values of 0.05 were considered to be statistically significant throughout.
  
  
  RESULTS
  Laboratory diagnoses based on IRMA were wholly in agreement with those based on CMIA. Furthermore, serum HBsAg levels by IRMA were found to be highly correlated with those determined by CMIA (correlation coefficient R (2) = 0.838, p < 0.001). Serum HBsAg level and serum HBV DNA copies were found to be linearly related by both methods (R (2) = 0.067, p = 0.316 by IRMA, and R (2) = 0.101, p = 0.215 by CMIA).
  
  
  CONCLUSIONS
  The diagnostic performance of the investigated IRMA method of determining HBsAg levels was found to be comparable with that of a CMIA-based method in chronic hepatitis B patients.
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Hyun-Woo
authors.initials: HW
authors.lastname: Kwon
authors.affiliation: Department of Nuclear Medicine, Seoul National University Boramae Medical Center, 39, Boramae-Gil, Dongjak-Gu, Seoul, 156-707 Korea ; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Korea.
authors.forename: Ho-Young
authors.initials: HY
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Seog Gyun
authors.initials: SG
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Boramae Medical Center, Seoul, Korea.
authors.forename: Yong Jin
authors.initials: YJ
authors.lastname: Jung
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea ; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Korea.
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea ; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Korea.
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea ; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Korea.
authors.forename: Myung Chul
authors.initials: MC
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul, Korea ; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Korea.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
keywords: Chemiluminescent microparticle immunoassay; Chronic hepatitis B; Hepatitis B virus surface antigen; Immunoradiometric assay