title: A single center's experience with noninvasive prenatal testing.
abstract: OBJECTIVE
  Massively parallel sequencing to detect fetal aneuploidy has high sensitivity and specificity for the detection of trisomies 21, 18, and 13 in high-risk populations. The purpose of our study was to review our institution's experience with the use of noninvasive prenatal testing for aneuploidy screening.
  
  
  METHODS
  This was a descriptive study of patients who had undergone noninvasive prenatal testing between January and September 2012 at the UNC Prenatal Diagnosis unit.
  
  
  RESULTS
  Two hundred and eight women had undergone noninvasive prenatal testing during the study period. The majority of patients were white (62.9%) and of advanced maternal age (71.2%). The fetal fraction was below the threshold in three obese patients (1.4%). An abnormal noninvasive prenatal test (aneuploidy detected or "unclassified" result) was reported in 6.3% (13/208) of the patients. Noninvasive prenatal testing had a combined sensitivity of 87.5% and specificity of 99.5% for detection of trisomies 21, 18, and 13. There were "unclassified" results in 11.1% (5/45) of the patients. Over the study period, the number of patients requesting noninvasive prenatal testing increased monthly. The rate of amniocenteses significantly declined (8.1% before vs. 5.3% after noninvasive prenatal testing, P < 0.01).
  
  
  CONCLUSIONS
  An increase in uptake of noninvasive prenatal testing and a significant decline in amniocentesis procedures were observed. The rates of "unclassified," false-positive, and false-negative results were higher than anticipated based on published preclinical trials.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine; University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Beamon
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine; University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Hardisty
authors.affiliation: University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Harris
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine; University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA.
authors.forename: Neeta L
authors.initials: NL
authors.lastname: Vora
mesh_terms: D000328:Adult; D000782:Aneuploidy; D005260:Female; D005865:Gestational Age; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D011248:Pregnancy Complications; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis / Q000379:methods; D055815:Young Adult