Improvement of algorithm based on free DNA fragment size for non-invasive prenatal test.
10.3760/cma.j.issn.1003-9406.2020.06.003
- Author:
Li ZHANG
1
;
Qian ZHU
;
Shanling LIU
;
He WANG
Author Information
1. Department of Obstetrics and Gynecology, Chengdu Integrated Traditional Chinese and Western Medicine Hospital, Chengdu First People's Hospital, Chengdu, Sichuan 610071, China. wanghe_cd@126.com.
- Publication Type:Journal Article
- From:
Chinese Journal of Medical Genetics
2020;37(6):609-612
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To derive more sensitive and accurate Z-scores for noninvasive prenatal testing of fetal trisomies based on a combined DNA count- and size- algorithm.
METHODS:One hundred eighty women at a high risk for fetal aneuploidies underwent amniocentesis. An effective cut-off value for DNA size ratio was explored. Conventional count-based Z-scores and size ratio-corrected Z scores were calculated. The reliability of each Z-score was assessed through comparison with the results of cytogenetic analysis.
RESULTS:With the cut-off value set as 150 bp, the ratio of small DNA is positively correlated with the proportion of fetal DNA. The sensitivity and specificity of conventional count-based Z-scores were 75.00%, and 98.86%, respectively. This rate has increased to nearly 100% with a count-based 150 bp size correction.
CONCLUSION:Compared with count-based methods alone, count-based Z-scores with 150 bp size correction may better predict fetal trisomies.
