title: Total hCG versus free beta-hCG combined with alpha-fetoprotein for Down syndrome screening in Taiwan.
abstract: OBJECTIVE
  The purpose of this study was to compare the effectiveness between total human chorionic gonadotropin (hCG) and free beta-hCG in two-marker Down syndrome screening programs during the second trimester in a Taiwanese population.
  
  
  METHODS
  From a multicenter collaborative study, we investigated the second-trimester maternal serum levels of total hCG from 67 data, free beta-hCG from 72 and alpha-fetoprotein (AFP) from 96 obtained from Taiwanese pregnant women carrying fetuses with Down syndrome.
  
  
  RESULTS
  High total hCG and free beta-hCG, as well as low AFP levels, were found with median values of 2.06, 2.49 and 0.77 multiples of the median (MoM), respectively. At a 5% false-positive rate, total hCG and free beta-hCG could detect 31% and 43% of Down syndrome pregnancies, respectively, whilst AFP alone could detect only 15% of affected cases. When combined with maternal age-specific risk, total hCG could achieve a 52% detection rate, free beta-hCG a 54% and AFP a 39%. Combined total hCG and AFP achieved a detection rate of 55%, and combined free beta-hCG and AFP achieved a rate of 60%.
  
  
  CONCLUSIONS
  The measurement of free beta-hCG is more beneficial than total hCG in serum screening for Down syndrome during the second trimester of pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: Tsang-Tang
authors.initials: TT
authors.lastname: Hsieh
authors.forename: Jenn-Jeih
authors.initials: JJ
authors.lastname: Hsu
authors.forename: Po-Jen
authors.initials: PJ
authors.lastname: Cheng
authors.forename: Chien-Nan
authors.initials: CN
authors.lastname: Lee
authors.forename: Hei-Jen
authors.initials: HJ
authors.lastname: Jou
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Chen
mesh_terms: D000328:Adult; D044466:Asian People; D006063:Chorionic Gonadotropin / Q000097:blood*; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods; D011237:Predictive Value of Tests; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D012189:Retrospective Studies; D013624:Taiwan; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: C097353:AFP protein, human; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D000509:alpha-Fetoproteins