title: Efficiency of manual scanning in recovering rare cellular events identified by fluorescence in situ hybridization: simulation of the detection of fetal cells in maternal blood.
abstract: Fluorescence in situ hybridization (FISH) and manual scanning is a widely used strategy for retrieving rare cellular events such as fetal cells in maternal blood. In order to determine the efficiency of these techniques in detection of rare cells, slides of XX cells with predefined numbers (1-10) of XY cells were prepared. Following FISH hybridization, the slides were scanned blindly for the presence of XY cells by different observers. The average detection efficiency was 84% (125/148). Evaluation of probe hybridization in the missed events showed that 9% (2/23) were not hybridized, 17% (4/23) were poorly hybridized, while the hybridization was adequate for the remaining 74% (17/23). In conclusion, manual scanning is a relatively efficient method to recover rare cellular events, but about 16% of the events are missed; therefore, the number of fetal cells per unit volume of maternal blood has probably been underestimated when using manual scanning.
authors.affiliation: Division of Genetics, Department of Pediatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, QC, Canada J1H 5N4.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Emad
authors.forename: Seemi
authors.initials: S
authors.lastname: Ayub
authors.forename: Oumar
authors.initials: O
authors.lastname: Samassékou
authors.forename: Marie-Chantal
authors.initials: MC
authors.lastname: Grégoire
authors.forename: Macoura
authors.initials: M
authors.lastname: Gadji
authors.forename: Aimé
authors.initials: A
authors.lastname: Ntwari
authors.forename: Josée
authors.initials: J
authors.lastname: Lamoureux
authors.forename: Francis
authors.initials: F
authors.lastname: Hemmings
authors.forename: Triantafyllos
authors.initials: T
authors.lastname: Tafas
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kilpatrick
authors.forename: Kada
authors.initials: K
authors.lastname: Krabchi
authors.forename: Régen
authors.initials: R
authors.lastname: Drouin
mesh_terms: D000328:Adult; D001773:Blood Cells / Q000737:chemistry / Q000166:cytology*; D005260:Female; D005333:Fetus / Q000166:cytology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods* / Q000592:standards; D008297:Male; D008954:Models, Biological; D011247:Pregnancy; D011296:Prenatal Diagnosis; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity