title: Digital PCR for noninvasive detection of aneuploidy: power analysis equations for feasibility.
abstract: OBJECTIVE
  To determine the feasibility of digital PCR analysis for noninvasive prenatal diagnosis of trisomy 21.
  
  
  METHODS
  Through power equations, we modeled the number of wells necessary to determine the feasibility of digital PCR as a practical method for trisomy 21 risk assessment.
  
  
  RESULTS
  The number of wells needed is a direct correlate of the ability to isolate free fetal DNA. If a 20% fetal DNA enhancement can be achieved, then 2,609 counts would be sufficient to achieve a 99% detection rate for a 1% false-positive rate and potentially feasible with readily available plates. However, if only a 2% increase is seen, then 220,816 counts will be necessary, and over 110,000 would be needed just to achieve 95% for a 5% false-positive rate - both far beyond current commercially available technology.
  
  
  CONCLUSIONS
  There are several noninvasive prenatal diagnostic methods which may reach commercialization; all have differing potential advantages and disadvantages. Digital PCR is potentially a cheaper methodology for trisomy 21, but it is too early to determine the optimal method.
authors.affiliation: Prenatal Diagnosis, Comprehensive Genetics, Columbia University, New York, NY 10065, USA. Evans@compregen.com
authors.forename: Mark I
authors.initials: MI
authors.lastname: Evans
authors.forename: David A
authors.initials: DA
authors.lastname: Wright
authors.forename: Eugene
authors.initials: E
authors.lastname: Pergament
authors.forename: Howard S
authors.initials: HS
authors.lastname: Cuckle
authors.forename: Kypros H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000782:Aneuploidy; D004247:DNA / Q000097:blood*; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005189:False Positive Reactions; D005240:Feasibility Studies; D005260:Female; D005333:Fetus; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000379:methods
chemical_list: D004247:DNA