Performance analysis of non-invasive prenatal testing for trisomy 13, 18, and 21: A large-scale retrospective study (2018–2021)

BackgroundNon-invasive prenatal tests (NIPT) are used to screen for trisomy 21, 18, and 13. This study investigated NIPT performance and the clinical significance of its results.MethodsPregnant women (n = 282,911) participating in a free NIPT (April 2018–December 2021) were screened for common trisomies, and the results were retrospectively analyzed. NIPT performance was evaluated by its positive predictive value (PPV), sensitivity, and specificity. Results were analyzed using number, percentage, and chi-squared/t-test analyses.ResultsAfter NIPT screening, patients with common trisomies (n = 746) included 457 with T21, 160 with T18, and 129 with T13. Seven false negative cases were identified. High PPV (86.81%, 56.81%, 18.18%), sensitivity (99.25%, 98.33%, 100.00%), and specificity (99.98%, 99.98%, 99.97%) values were detected for trisomy 21, 18, and 13, respectively. The PPVs of common trisomies were significantly different between pregnant women older than 35 (85.53%, 136/159) and those aged 35 or younger (58.90%, 311/528) (χ2 = 125.02, P = 2.20e-16). As the NIPT uptake increased from 2018 to 2021, live-born birth defect incidence decreased.ConclusionNIPT performed well in screening for T21, T18, and T13. Our discoveries offer an important and useful guideline in laboratory and clinical genetic counseling.