title: Prenatal diagnosis by in situ hybridization on uncultured amniocytes: reduced sensitivity and potential risk of misdiagnosis in blood-stained samples.
abstract: Maternal cell contamination was assessed in 18 macroscopically blood-stained amniotic fluid samples from male fetuses. The samples were analysed by double-target fluorescent in situ hybridization (ISH) with Y and X chromosome-specific probes. The only sample with an aberrant karyotype (47,XY, + 18) was also analysed by hybridization with a chromosome 18-specific probe. An interpretation of extensive maternal cell contamination was made in two samples, one of which was the sample with trisomy 18. ISH with the chromosome 18-specific probe on this latter sample showed that the sensitivity of the ISH method for chromosome enumeration of uncultured amniotic fluid samples may be reduced in blood-stained samples. It was calculated that by using ISH for chromosome enumeration of the two extensively contaminated samples, a case of trisomy 21 might have been overlooked in both samples, while a case of trisomy 18 might only have been overlooked in one of the samples. It is concluded that ISH should not be used for chromosome enumeration of uncultured amniotic fluid samples that are macroscopically blood-stained without further technical developments.
authors.affiliation: Department of Obstetrics and Gynaecology, University Hospital, Copenhagen, Denmark.
authors.forename: B
authors.initials: B
authors.lastname: Christensen
authors.forename: T
authors.initials: T
authors.lastname: Bryndorf
authors.forename: J
authors.initials: J
authors.lastname: Philip
authors.forename: Y
authors.initials: Y
authors.lastname: Xiang
authors.forename: W
authors.initials: W
authors.lastname: Hansen
mesh_terms: D000653:Amniotic Fluid / Q000166:cytology*; D001801:Blood Stains; D002869:Chromosome Aberrations / Q000502:physiology*; D015342:DNA Probes; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014960:X Chromosome; D014998:Y Chromosome
chemical_list: D015342:DNA Probes