title: Comparison of multiple-marker screening with amniocentesis for the detection of fetal aneuploidy in women > or = 35 years old.
abstract: OBJECTIVE
  Our purpose was to compare the multiple-marker screening test with elective amniocentesis for the detection of fetal Down syndrome and other aneuploidies in women aged > or = 35.
  
  
  METHODS
  Our database included the multiple-marker screening test (maternal serum alpha-fetoprotein, human chorionic gonadotropin, unconjugated estriol, and maternal age) and genetic amniocentesis results from 1942 women aged > or = 35. A Down syndrome risk > or = 1:190 was considered screen positive. An algorithm to detect trisomy 18 was also used.
  
  
  RESULTS
  The multiple-marker screening test Down syndrome screen-positive rate was 26.1% (507/1942). The Down syndrome detection rate was 75% (33/44); the trisomy 18 detection rate was 75% (3/4). However, the multiple-marker screening test detection rate for all aneuploidies was only 61%. Missed aneuploidies included trisomy 21, sex chromosome abnormalities, trisomy 13, trisomy 22, and trisomy 18.
  
  
  CONCLUSIONS
  The multiple-marker screening test fails to detect approximately 39% of all fetal aneuploidies in women aged > or = 35. These data should be provided to women considering prenatal diagnosis so that they can make an informed decision regarding the multiple-marker screening test versus amniocentesis for advanced maternal age.
mesh_terms: D000328:Adult; D000649:Amniocentesis; D000782:Aneuploidy; D015415:Biomarkers / Q000097:blood; D006063:Chorionic Gonadotropin / Q000097:blood; D002869:Chromosome Aberrations / Q000175:diagnosis* / Q000235:genetics; D025063:Chromosome Disorders; D004314:Down Syndrome / Q000175:diagnosis; D004964:Estriol / Q000097:blood; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D011296:Prenatal Diagnosis; D011446:Prospective Studies; D012189:Retrospective Studies; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D015415:Biomarkers; D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol