title: QF-PCR as a substitute for karyotyping of cytotrophoblast for the analysis of chorionic villi: advantages and limitations from a cytogenetic retrospective audit of 44,727 first-trimester prenatal diagnoses.
abstract: OBJECTIVE
  Karyotyping on chorionic villous samples (CVS) includes the analysis of both cytotrophoblast (STC) and mesenchyme (LTC). This approach requires complex laboratory organization and trained technicians. The introduction of quantitative fluorescent polymerase chain reaction (QF-PCR) instead of conventional karyotyping in low-risk pregnancies opened its application in CVS analysis. Discordant QF-PCR and CVS cytogenetic results were reported, and strategies for CVS analysis were introduced to minimize this risk. The possibility to substitute the STC with QF-PCR was reported. The aim of this study is to evaluate benefits and limitations of the approach QF-PCR + LTC compared with the traditional method STC + LTC and to quantify the associated risks of false results.
  
  
  METHODS
  This study is based on a retrospective cytogenetic audit of CVS results (n = 44 727) generated by the STC + LTC analytic approach. False-negative risks related to true fetal mosaicism type IV, imprinting syndromes and maternal contamination in LTC were calculated.
  
  
  RESULTS
  Compared with STC + LTC, QF-PCR + LTC approach is associated with a cumulative false-negative risk of ~1/3100-1/4400. Costs and reporting time of STC in a high-throughput cytogenetic lab are similar to a CE-IVD marked QF-PCR analysis.
  
  
  CONCLUSIONS
  These results should be clearly highlighted in the pre-test counseling and extensively discussed with the couple prior to testing for informed consent.
authors.affiliation: Research and Development, Cytogenetics and Molecular Biology, TOMA Advanced Biomedical Assays, Busto Arsizio, VA, Italy. fgrati@tomalab.com
authors.forename: Francesca R
authors.initials: FR
authors.lastname: Grati
authors.forename: Francesca
authors.initials: F
authors.lastname: Malvestiti
authors.forename: Beatrice
authors.initials: B
authors.lastname: Grimi
authors.forename: Elisa
authors.initials: E
authors.lastname: Gaetani
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Di Meco
authors.forename: Anna
authors.initials: A
authors.lastname: Trotta
authors.forename: Rosaria
authors.initials: R
authors.lastname: Liuti
authors.forename: Sara
authors.initials: S
authors.lastname: Chinetti
authors.forename: Francesca
authors.initials: F
authors.lastname: Dulcetti
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Ruggeri
authors.forename: Cristina
authors.initials: C
authors.lastname: Agrati
authors.forename: Giuditta
authors.initials: G
authors.lastname: Frascoli
authors.forename: Silvia
authors.initials: S
authors.lastname: Milani
authors.forename: Simona
authors.initials: S
authors.lastname: De Toffol
authors.forename: Lorenza
authors.initials: L
authors.lastname: Martinoni
authors.forename: Silvia
authors.initials: S
authors.lastname: Paganini
authors.forename: Livia
authors.initials: L
authors.lastname: Marcato
authors.forename: Federico
authors.initials: F
authors.lastname: Maggi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Simoni
mesh_terms: D002824:Chorionic Villi; D015193:Chorionic Villi Sampling / Q000706:statistics & numerical data; D002869:Chromosome Aberrations / Q000706:statistics & numerical data; D054869:Clinical Audit; D003362:Cost-Benefit Analysis; D005260:Female; D005453:Fluorescence; D006801:Humans; D007621:Karyotyping / Q000191:economics / Q000379:methods; D057230:Limit of Detection; D016133:Polymerase Chain Reaction / Q000191:economics / Q000379:methods*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis / Q000191:economics / Q000379:methods*; D012189:Retrospective Studies; D014327:Trophoblasts