An external quality assessment scheme for prenatal detection of rare chromosomal abnormalities.
OBJECTIVE
To improve the accuracy of prenatal cytogenetic diagnosis by establishing an external quality assessment (EQA) scheme for rare, or subtle, structural chromosomal abnormalities.


METHODS
Typical metaphase images of rare chromosomal abnormalities along with an anonymized clinical history were sent to 35 prenatal diagnosis laboratories. The laboratories were required to provide independent reports using current nomenclature. Evaluation of reports was based on established criteria for quality assessment of karyotype analysis.


RESULTS
Totally 6 kinds of typical rare chromosomal abnormalities were collected. 35 laboratories were enrolled with a response rate of 94.29%. The overall analytical accuracy is 82.20%. This is comparable with our former EQA scheme using established lymphocyte cell lines with rare abnormal chromosome karyotypes (χ²=0.065, P=0.799).


CONCLUSIONS
Introduction of efficient EQA for prenatal genetic diagnosis is currently imperative, due to the limited performances of karyotype analysis of rare chromosomal abnormalities. Metaphase images could be used as a simple and effective material for EQA and to improve the quality of prenatal genetic diagnosis.
Women's Reproductive Health Laboratory of Zhejiang Province, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
Binghuan
B
Weng
Xiao
X
Li
D002869:Chromosome Aberrations; D025063:Chromosome Disorders / Q000175:diagnosis; D020732:Cytogenetic Analysis / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D007621:Karyotyping; D059021:Laboratory Proficiency Testing; D008677:Metaphase; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods / Q000592:standards*