title: Prospective prenatal serum screening for Down syndrome in Venezuela.
abstract: OBJECTIVE
  To assess the usefulness of triple-marker screening for Down syndrome in Venezuela.
  
  
  METHODS
  Maternal serum concentrations of alpha fetoprotein (AFP), beta human chorionic gonadotropin (beta-hCG), and unconjugated estriol (uE3) were measured weekly in 3895 women from the 15th to the 20th week of pregnancy. Population-specific likelihood ratios were determined and used to calculate the risk of fetal Down syndrome for each pregnancy.
  
  
  RESULTS
  The median multiple of the median values for AFP, beta-hCG, and uE3 concentrations were 0.69, 2.10, and 0.67 for the affected pregnancies. The likelihood ratio for a positive result was 1:19. The detection and false-positive rates were 69.23% and 5.8%.
  
  
  CONCLUSIONS
  These findings were consistent with reported data and therefore confirmed triple-marker serum screening as effective and suitable for prenatal care in Venezuela. Latin American governments and Health Agencies should recommend offering this screening method to all pregnant women.
authors.affiliation: Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela. falvareznava@yahoo.com
authors.forename: Francisco
authors.initials: F
authors.lastname: Alvarez-Nava
authors.forename: Marisol
authors.initials: M
authors.lastname: Soto
authors.forename: Alisandra
authors.initials: A
authors.lastname: Morales-Machín
authors.forename: Alicia
authors.initials: A
authors.lastname: Rojas
authors.forename: Karelis
authors.initials: K
authors.lastname: Urdaneta
authors.forename: Jenny
authors.initials: J
authors.lastname: Cañizález
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D004964:Estriol / Q000097:blood*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D016015:Logistic Models; D008423:Maternal Age; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods*; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors; D018709:Statistics, Nonparametric; D014687:Venezuela / Q000453:epidemiology; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D000509:alpha-Fetoproteins; D004964:Estriol