title: Hyperglycosylated-hCG (h-hCG) and Down syndrome screening in the first and second trimesters of pregnancy.
abstract: OBJECTIVE
  To validate Down syndrome screening protocols that include hyperglycosylated-hCG (h-hCG) measurements.
  
  
  METHODS
  Measuring h-hCG in 21 641 fresh first- and second-trimester maternal serum samples, but not for clinical interpretation. Nuchal translucency (NT) and pregnancy associated plasma protein-A (PAPP-A) measurements were available in the first trimester; alpha-fetoprotein (AFP), unconjugated estriol (uE3), and human chorionic gonadotropin (hCG) measurements in the second trimester.
  
  
  RESULTS
  Of the 23 first- and 26 second-trimester Down syndrome pregnancies identified, 52 and 65% of h-hCG measurements were above the 95th centile, respectively. At a 3% false positive rate, maternal age, NT, PAPP-A and h-hCG detected 78% of cases (95% CI, 56-93%). Other combinations were consistent with previous modeling utilizing stored samples. A literature summary indicates h-hCG is as strong a marker as free-beta between 10 and 13 weeks' gestation.
  
  
  CONCLUSIONS
  Down syndrome screening performance of h-hCG using fresh samples meets published expectations based on stored samples. h-hCG could replace free beta measurements, at gestational ages as early as 10 weeks.
authors.affiliation: Women & Infants Hospital/Brown University Providence, Rhode Island 02903, USA. gpalomaki@ipmms.org
authors.forename: Glenn E
authors.initials: GE
authors.lastname: Palomaki
authors.forename: Louis M
authors.initials: LM
authors.lastname: Neveux
authors.forename: James E
authors.initials: JE
authors.lastname: Haddow
authors.forename: Philip
authors.initials: P
authors.lastname: Wyatt
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood*; D015331:Cohort Studies; D004314:Down Syndrome / Q000175:diagnosis*; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D011262:Pregnancy Trimester, Second / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods*
chemical_list: D006063:Chorionic Gonadotropin; C024889:glycosylated HCG