title: [Methodological study on magnetic enzymic immunoassay for detecting free hCGbeta subunit].
abstract: OBJECTIVE
  To establish a novel magnetic enzyme immunoassay (MEIA) for detecting human choriogonadotropin free beta subunit (hCGbeta).
  
  
  METHODS
  Two monoclonal antibodies (mAb) were used for conjugating with FITC and with alkaline phosphatase(AP) respectively, which incorporated magnetic solid phase separation. Magnetic beads were coupled with sheep anti-FITC antibody as solid phase, and phenolphthalein monophosphate was used as substrate to set up MEIA for detecting hCGbeta.
  
  
  RESULTS
  The sensitivity of hCGbeta MEIA kit reached 0.1 IU/L. The intraassay variation and inter-assay variation was 8.5% and 14% respectively, with the average recovery rate of dilution of 92.5%. The kit showed no cross reactivity to LH, TSH and FSH, while a cross reactivity of 1.2% to intact hCG at concentration of 1000 IU/L. The time of efficacy of hCGbeta MEIA kit was longer than 14 months.
  
  
  CONCLUSIONS
  hCGbeta MEIA kit is better than hCGbeta radio immunoassay and ELISA kit, which can provide a high-qualitative and cheap hCGbeta kit for market.
authors.affiliation: Biology Science and Technology College, Huazhong Science and Technology University, Wuhan 430070, China. zhenshi-liu@sohu.com
authors.forename: Zhen-shi
authors.initials: ZS
authors.lastname: Liu
authors.forename: Hao
authors.initials: H
authors.lastname: Zhou
authors.forename: Hai-sheng
authors.initials: HS
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.forename: Xin
authors.initials: X
authors.lastname: Lu
authors.forename: Xiang-liang
authors.initials: XL
authors.lastname: Yang
mesh_terms: D000911:Antibodies, Monoclonal / Q000032:analysis; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000032:analysis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007124:Immunoenzyme Techniques / Q000379:methods*; D008280:Magnetics; D008722:Methods; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D018997:Chorionic Gonadotropin, beta Subunit, Human