The value of non-invasive prenatal genetic testing as first-trimester screening / 中华检验医学杂志

ABSTRACT

Objective To evaluate the value of non-invasive prenatal testing (NIPT) as first-trimester screen (FTS) for the detection of trisomies 21, 18 and 13. Methods This was a retrospective study. 8517 pregnancies who performed NIPT at Obstetrics and Gynecology Hospital of Fudan University from 2017 May to 2018 June. 14 cases (0.16％) were failed. 8503 pregnancies were divided into 2 groups:NIPT joint traditional screening, NIPT. High risk pregnancies were verified by prenatal diagnosis. Evaluate the performance of NIPT. All pregnancies were followed up. Frequencies were compared with Fisher′s exact test. Results 8517 pregnancies underwent NIPT. 14 cases (0.16％) were failed. 83 cases of remaining 8503 cases had high risk results, among which 29 were trisomy 21, 14 were trisomy 18, 6 were trisomy 13 and 34 were sex chromosome aneuploidies (SCA). In 2996 cases who underwent NIPT joint traditional screening, NIPT found 14 cases of common aneuploidies 12 cases of SCA. 11 and 3 cases were validated by invasive prenatal diagnosis, respectively. In 5507 NIPT cases, 35 cases of common aneuploidies and 22 cases of SCA were found, among which 29 and 11 cases were validated. There was no significant differences between two groups for common aneuploidies (P=1.00). The sensitivity were 11/11 and 29/29 respectively,the specificity were 99.90％(2982/2985) and 99.89％(5472/5478), the positive predictive value (PPV) were 78.57％(11/14) and 82.86％(29/35), the negative predictive value (NPV) were 100％(2982/2982) and 100％ (5472/5472), respectively. Besides, the sensitivity and PPV of NIPT for SCA were 100％ and 41.18％. No false negative was found. Conclusions The proportion of pregnancies underwent NIPT alone was 64.77％. NIPT had excellent performance (the specificity and PPV) for common aneuploidies, and also had a certain value for SCA, which greatly reduced in invasive diagnosis. NIPT is a commendable essay as a first-line prenatal screening. Invasive diagnosis is still necessary for pregnancies with high-risk of NIPT.