title: Gestation related karyotype, QF-PCR and CGH-array failure rates in diagnostic amniocentesis.
abstract: BACKGROUND
  Few data exist describing laboratory related failure rates in prenatal diagnosis. The aim of this study is to assess the laboratory associated failure rate for karyotype, QF-PCR and CGH-array following amniocentesis in relation to gestation.
  
  
  METHODS
  Retrospective database study of amniocenteses performed 2004-2014 comparing laboratory failure rate for karyotype, QF-PCR and CGH-array between 16 + 0 and 40 + 0 weeks' gestation.
  
  
  RESULTS
  A total of 10 484 amniotic fluid test results were collected in three databases. Karyotype failed in 41/1797 (2.3%) tests; failure rate was significantly greater with advancing gestation reaching 43% at 36-40 weeks. QF-PCR failed in 132/5715 tests (2.3%) and was significantly greater with advancing gestation reaching 7% at 36-40 weeks. For CGH-array, 10/298 tests (3.4%) failed analysis. In one case, no result was obtainable by any technique.
  
  
  CONCLUSIONS
  These data provide gestation specific laboratory failure rates for amniocentesis enabling informed decisions about the timing and laboratory technique most applicable to the clinical situation. Before 20 weeks, karyotype is least likely to fail of the three techniques. However, in the late third trimester, QF-PCR and, in particular, karyotyping are more likely to fail than CGH-array. Although there is some overlap between the three different tests, they may be preferentially offered in different clinical scenarios. © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, Imperial College, London, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Lawin O'Brien
authors.affiliation: Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, Imperial College, London, UK.|Department of Obstetrics and Gynaecology, University of Parma, Parma, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Dall'Asta
authors.affiliation: Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, Imperial College, London, UK.
authors.forename: Dagmar
authors.initials: D
authors.lastname: Tapon
authors.affiliation: Genetics Laboratories, Viapath Analytics, Guys and St Thomas' Hospital Foundation Trust, London, UK.
authors.forename: Kathy
authors.initials: K
authors.lastname: Mann
authors.affiliation: Genetics Department, Guys and St Thomas' Hospital Foundation Trust, London, UK.
authors.forename: Joo Wook
authors.initials: JW
authors.lastname: Ahn
authors.affiliation: North West Thames Regional Genetics Service, London, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Ellis
authors.affiliation: Genetics Department, Guys and St Thomas' Hospital Foundation Trust, London, UK.|King's College, London, UK.
authors.forename: Caroline
authors.initials: C
authors.lastname: Ogilvie
authors.affiliation: Centre for Fetal Care, Queen Charlotte's and Chelsea Hospital, Imperial College, London, UK.|Department of Surgery and Cancer, Imperial College London, London, UK.|Department of Development and Regeneration, KU Leuven, Belgium.
authors.forename: Christoph
authors.initials: C
authors.lastname: Lees
mesh_terms: D000649:Amniocentesis; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000235:genetics; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D055028:Comparative Genomic Hybridization; D016208:Databases, Factual; D004314:Down Syndrome / Q000175:diagnosis / Q000235:genetics; D005260:Female; D005453:Fluorescence; D005865:Gestational Age; D006801:Humans; D007621:Karyotyping; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012189:Retrospective Studies; D012729:Sex Chromosome Aberrations; D014314:Trisomy / Q000175:diagnosis / Q000235:genetics; D000073839:Trisomy 13 Syndrome; D000073842:Trisomy 18 Syndrome