title: Patient's choice between a non-invasive prenatal test and invasive prenatal diagnosis based on test accuracy.
abstract: OBJECTIVE
  To assess how pregnant women choose between a non-invasive DNA test (NIDT) and an invasive prenatal test (IPD) based on the accuracy of the test.
  
  
  METHODS
  Pregnant women who attended for first-trimester combined screening assessment of risk of Down syndrome were invited to participate in an interviewer-administered survey. Women were asked to choose between NIDT (variable detection rate but no miscarriage risk) and IPD (∼100% detection rate but 0.5-1% miscarriage risk) if their screening test was positive for Down syndrome using the standard gamble technique.
  
  
  RESULTS
  358 women were approached of which 106 (29.6%) were unwilling to participate in the study as it had already been decided in advance which additional test they would have if they were screened positive. Of these 106 women, 70 (19.6%) would only choose IPD whereas 36 (10%) would only choose NIDT. Among those who agreed to undertake the gamble and participate in the study (n=252), 50% were willing to accept NIDT as an alternative to IPD provided that NIDT had a detection rate of 95%.
  
  
  CONCLUSIONS
  The majority can accept NIDT as an alternative to IPD provided that the test is 95% accurate in the diagnosis of Down syndrome. Current evidence indicates that the detection rate of NIDT will be higher than this level. Health professionals should consider NIDT as an alternative to IPD when counseling women with a positive screening test.
authors.affiliation: Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China.
authors.forename: Yiu Man
authors.initials: YM
authors.lastname: Chan
authors.forename: Tak Yeung
authors.initials: TY
authors.lastname: Leung
authors.forename: Oi Ka Catherine
authors.initials: OK
authors.lastname: Chan
authors.forename: Yvonne Kwun Yue
authors.initials: YK
authors.lastname: Cheng
authors.forename: Daljit Singh
authors.initials: DS
authors.lastname: Sahota
mesh_terms: D000328:Adult; D002474:Cell-Free System / Q000502:physiology; D002755:Choice Behavior; D003625:Data Collection / Q000379:methods*; D004314:Down Syndrome / Q000175:diagnosis / Q000235:genetics; D005260:Female; D006801:Humans; D008423:Maternal Age; D010358:Patient Participation / Q000523:psychology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000235:genetics / Q000523:psychology*; D011296:Prenatal Diagnosis / Q000009:adverse effects / Q000523:psychology*; D011446:Prospective Studies