title: Triple-marker prenatal screening program for chromosomal defects.
abstract: OBJECTIVE
  To examine screening performance of California's triple-marker screening program, using data from a statewide registry for chromosomal defects.
  
  
  METHODS
  This study included 752,686 women who received a screening risk and had an expected date of delivery between July 2005 and the end of June 2007. Follow-up diagnostic services for screen-positive women were performed at state-approved centers. Data on diagnostic outcomes from these visits were entered into the California Chromosomal Defect Registry (CCDR). Other CCDR sources include mandatory reporting by all cytogenetic laboratories and hospitals and outcome data forms submitted by prenatal care providers.
  
  
  RESULTS
  The observed detection rate for Down syndrome (N=1,217) was 77.4%. It varied significantly by gestational dating method and maternal age. The rates for women aged younger than 35 years and 35 years and older were 62.4% and 94.0%, respectively. The detection rates were 81.3% for ultrasound-dated pregnancies and 67.5% for last menstrual period-dated pregnancies. For Turner syndrome, trisomy 18, triploidy, and trisomy 13, the detection rates were 79.4%, 82.5%, 98.1%, and 36.0%, respectively. The positive rate for Down syndrome was 5.4%. Of women with a Down syndrome fetus who were screen positive, only 49.5% opted for amniocentesis. Of women who obtained results from amniocentesis indicating a Down syndrome fetus, 61.4% had an elective termination, 26.2% had a live birth, 4.5% had a death or miscarriage, and 7.9% had an unknown outcome.
  
  
  CONCLUSIONS
  The observed performance of this large triple-marker screening program exceeds generally predicted detection rates for Down syndrome. This study methodology will be used to measure the performance of subsequent screening enhancements.
  
  
  METHODS
  III.
authors: From the Genetic Disease Screening Program, California Department of Public Health, Richmond, California.
authors: N Neely
authors: NN
authors: Kazerouni
authors: Bob
authors: B
authors: Currier
authors: Linda
authors: L
authors: Malm
authors: Susan
authors: S
authors: Riggle
authors: Christina
authors: C
authors: Hodgkinson
authors: Sylvia
authors: S
authors: Smith
authors: Corinna
authors: C
authors: Tempelis
authors: Fred
authors: F
authors: Lorey
authors: Amber
authors: A
authors: Davis
authors: Laura
authors: L
authors: Jelliffe-Pawlowski
authors: Lynn
authors: L
authors: Walton-Haynes
authors: Marie
authors: M
authors: Roberson
mesh_terms: D000293:Adolescent; D000328:Adult; D000649:Amniocentesis; D002648:Child; D025063:Chromosome Disorders / Q000175:diagnosis*; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005865:Gestational Age; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D009261:Nail-Patella Syndrome / Q000175:diagnosis; D011247:Pregnancy; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis / Q000379:methods*; D014314:Trisomy / Q000175:diagnosis; D016216:Ultrasonography, Prenatal; D055815:Young Adult