Rapid testing versus karyotyping in Down's syndrome screening: cost-effectiveness and detection of clinically significant chromosome abnormalities.
In all, 80% of antenatal karyotypes are generated by Down's syndrome screening programmes (DSSP). After a positive screening, women are offered prenatal foetus karyotyping, the gold standard. Reliable molecular methods for rapid aneuploidy diagnosis (RAD: fluorescence in situ hybridization (FISH) and quantitative fluorescence PCR (QF-PCR)) can detect common aneuploidies, and are faster and less expensive than karyotyping.In the UK, RAD is recommended as a standalone approach in DSSP, whereas the US guidelines recommend that RAD be followed up by karyotyping. A cost-effectiveness (CE) analysis of RAD in various DSSP is lacking. There is a debate over the significance of chromosome abnormalities (CA) detected with karyotyping but not using RAD. Our objectives were to compare the CE of RAD versus karyotyping, to evaluate the clinically significant missed CA and to determine the impact of detecting the missed CA. We performed computer simulations to compare six screening options followed by FISH, PCR or karyotyping using a population of 110948 pregnancies. Among the safer screening strategies, the most cost-effective strategy was contingent screening with QF-PCR (CE ratio of $24084 per Down's syndrome (DS) detected). Using karyotyping, the CE ratio increased to $27898. QF-PCR missed only six clinically significant CA of which only one was expected to confer a high risk of an abnormal outcome. The incremental CE ratio (ICER) to find the CA missed by RAD was $66608 per CA. These costs are much higher than those involved for detecting DS cases. As the DSSP are mainly designed for DS detection, it may be relevant to question the additional costs of karyotyping.
Gekas
Jean
J
Centre de Recherche du CHUQ, Service de Génétique Médicale, Unité de Diagnostic Prénatal, Département de Pédiatrie, Université Laval, Québec City, Québec, Canada. jean.gekas@mail.chuq.qc.ca
van den Berg
David-Gradus
DG
Durand
Audrey
A
Vallée
Maud
M
Wildschut
Hajo Izaäk Johannes
HI
Bujold
Emmanuel
E
Forest
Jean-Claude
JC
Rousseau
François
F
Reinharz
Daniel
D
D000328:Adult; D002869:Chromosome Aberrations; D003362:Cost-Benefit Analysis; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D005820:Genetic Testing / Q000191:economics* / Q000379:methods; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000191:economics; D007231:Infant, Newborn; D007621:Karyotyping / Q000379:methods*; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000191:economics; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000191:economics* / Q000379:methods; D013997:Time Factors; D055815:Young Adult