title: Analytic evaluation of the beta-human chorionic gonadotropin assay on the Abbott IMx and Elecsys2010 for its use in doping control.
abstract: OBJECTIVE
  The principal objective of this study was to compare the analytical performance of the Elecsys2010 (Roche Diagnostics) system with the IMx (Abbott laboratories) system for beta-hCG assay in order to assess its possible utility as a confirmation test for the quantitative measurement of beta-hCG in urine for doping control purposes.
  
  
  METHODS
  Urine samples with spiked standard known concentrations of beta-hCG and different urine samples from athletes were used in order to determine the calibration curve stability and linearity, detection limit, total, within-run and between-run precision, and method comparison for the IMx and Elecsys2010 systems for beta-hCG assay, along with the stability of samples, at room temperature and at 4 degrees C.
  
  
  RESULTS
  The IMx assay was linear up to 500 IU/L, whereas the Elecsys2010 assay was linear up to 1000 IU/L. The detection limit for the IMx and Elecsys2010 systems were 0.75 IU/L and 0.25 IU/L, respectively. The total precision of the IMx and Elecsys2010 systems were <or=5% for beta-hCG concentrations ranging from 20 to 900 IU/L and from 6.67 to 55.2 IU/L, respectively. The within-run precision tests for the IMx and Elecsys2010 systems yielded CV results of 2-3% and 3-4% respectively, while the between-run precision for the Elecsys2010 was less than 4%, whereas that of IMx was 9-16%. Regression analysis with spiked urine samples yielded the following: slope (SD) 0.7104 (0.003) and y-intercept (SD) -0.4286 (1.397) (Sy.x=2.328; r=0.9999; n=5), whereas regression analysis using the athletes' urine samples yielded the following results: slope (SD) 0.3692 (0.003) and y-intercept (SD) 0.0016 (0.003) (Sy.x=0.0096; r=0.9924; n=100). Sample stability studies evidenced a nonsignificant effect at 4 degrees C and room temperature (25 degrees C) for up to 1 month.
  
  
  CONCLUSIONS
  For doping control, the IMx and Elecys2010 may be used to screen and confirm the presence of beta-hCG in urine of athletes, respectively. Additional studies are needed to verify this finding. This study also underscores the need for beta-hCG assays standardization for doping control.
authors: Bioanalysis and Biotransformation Center, Korea Institute of Science and Technology, 130-650, Hawolgokdong 39-1, Seoul, Korea.
authors: Khurram
authors: K
authors: Shahzad
authors: Dong-Hyun
authors: DH
authors: Kim
authors: Min-Jung
authors: MJ
authors: Kang
mesh_terms: D002138:Calibration; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000592:standards / Q000652:urine*; D019963:Clinical Chemistry Tests / Q000295:instrumentation* / Q000379:methods; D004300:Doping in Sports / Q000517:prevention & control*; D006801:Humans; D012015:Reference Standards; D012044:Regression Analysis; D015203:Reproducibility of Results
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human