Objective      To verify the accuracy and effectiveness of a genetic detection kit for noninvasive fetal trisomy (T21

T18 and T13

based on combinatorial probe-anchor ligation sequencing

a product of BGI Biotechnology Limited Co.) in clinical practice.        Methods      Pregnant women who underwent prenatal diagnosis in our hospital were recruited in this study. Maternal peripheral blood samples were collected from each participant

and then processed in accordance with the kit instructions followed by combinatorial probe-anchor ligation sequencing. The results were compared with the results from prenatal karyotyping confirmation and baby born. The sensitivity

specificity

overall compliance rate and consistency coefficient Kappa values were evaluated to verify the accuracy and validity of the kit in the clinical testing.       Results      A total of 389 valid samples was tested using this genetic testing kit. Six pregnant women were found carrying trisomy 21 fetuses by sequencing

and none of them carrying trisomy 18 or 13 fetus

which consistent with the results of karyotyping. The other 383 women were negative

which was further validated by telephone follow-up after baby born. Statistical analysis showed that the total coincidence rate of our sequencing and karyotyping was 100% and the Kappa=1 (≥0.8)

indicating that the sensitivity

specificity

positive predictive value and negative predictive value of trisomy 21 were 100%

and the specificity

negative predictive value of trisomy 18 and trisomy 13 were 100%.       Conclusion      This genetic detection kit for noninvasive fetal trisomy is of high accuracy and security

and should be worth of extensive application in clinic．