QF-PCR as a stand-alone test for prenatal samples: the first 2 years' experience in the London region.
OBJECTIVE
To analyse the results of the first 2 years of a QF-PCR stand-alone testing strategy for the prenatal diagnosis of aneuploidy in the London region and to determine the advantages and disadvantages of this policy.


METHODS
A review of the results of 9737 prenatal samples received for exclusion of chromosome abnormalities. All samples were subjected to QF-PCR testing for common aneuploidies but only samples fulfilling specific criteria subsequently had a full karyotype analysis.


RESULTS
Of the 9737 samples received, 10.3% had a chromosome abnormality detected by QF-PCR testing. Of the 7284 samples received with no indication for karyotype analysis, 25 (0.3%) received a normal QF-PCR result but subsequently had an abnormal karyotype detected either prenatally as a privately funded test or postnatally. Of these samples, without subsequent abnormal ultrasound findings, five had a chromosome abnormality associated with a poor prognosis, representing 0.069% of samples referred for Down syndrome testing.


CONCLUSIONS
While back-up karyotyping is required for some samples, using QF-PCR as a stand-alone prenatal test for pregnancies without ultrasound abnormalities reduces costs, provides rapid delivery of results, and avoids ambiguous and uncertain karyotype results, reducing parental anxiety.
Cytogenetics Department, GSTS Pathology, Guy's and St Thomas' NHS Foundation Trust, London, UK. alison.hills@gsts.com
Alison
A
Hills
Celia
C
Donaghue
Jonathan
J
Waters
Katie
K
Waters
Caroline
C
Sullivan
Abhijit
A
Kulkarni
Zoe
Z
Docherty
Kathy
K
Mann
Caroline Mackie
CM
Ogilvie
D000465:Algorithms; D000782:Aneuploidy; D001800:Blood Specimen Collection / Q000592:standards; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000235:genetics; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D007621:Karyotyping / Q000379:methods; D008131:London / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods* / Q000706:statistics & numerical data; D012107:Research Design; D012189:Retrospective Studies