title: The "Consecutive Combined Test"--using double test from week 8 + 0 and nuchal translucency scan, for first trimester screening for Down syndrome.
abstract: OBJECTIVE
  To test the performance of the "Consecutive Combined Test", applied on a high-risk population. The classic "Combined Test" (Double test (DT) and Nuchal Translucency (NT) measurement on the same day at app. week 12) gives detection rates (DR) for Down syndrome (DS) of 80-90% for false positive rates (FPR) of 5%. In affected pregnancies, however, the low PAPP-A level is more pronounced, the earlier in pregnancy. Thus, we hypothesized that the Double Test could be taken as early as from week 8 + 0, without compromising the excellent performance of the Combined Test. This "Consecutive Combined Test" allows for a centralised laboratory function.
  
  
  METHODS
  Inclusion criteria were maternal age > 35 years (80%) or a family history (20%). Double test was taken at a median gestational age (GA) = 10 weeks. NT was measured at GA = 11 + 0 - 13 + 6. A combined risk estimate of > 1:400 at birth was used as cut-off.
  
  
  RESULTS
  881 had the full test. Screen positive = 34. CVS with aneuploidy = 11 (6 trisomy-21, 5 others). FPR = 3.2%. Positive Predictive Value (PPV) = 17.6% for T-21.
  
  
  CONCLUSIONS
  The "Consecutive Combined Test" applied on a high-risk population seems to be highly efficient with a remarkably high PPV.
authors.affiliation: Skejby University Hospital, Aarhus, Denmark. kms@dadlnet.dk
authors.forename: Kirsten Marie
authors.initials: KM
authors.lastname: Schiøtt
authors.forename: Michael
authors.initials: M
authors.lastname: Christiansen
authors.forename: Olav Bjørn
authors.initials: OB
authors.lastname: Petersen
authors.forename: Tina Lind
authors.initials: TL
authors.lastname: Sørensen
authors.forename: Niels
authors.initials: N
authors.lastname: Uldbjerg
mesh_terms: D000328:Adult; D000782:Aneuploidy; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004314:Down Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008423:Maternal Age; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis; D011296:Prenatal Diagnosis / Q000379:methods
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A