Non-invasive prenatal testing (NIPT) uses cell-free DNA (cfDNA) in maternal blood and has very high sensitivity and specificity when screening for abnormalities such as trisomies 21, 18 and 13. In large studies, the sensitivity for trisomies 21, 18 and 13 was 99.7%, 97.9% and 99%, respectively, while the false-positive rate (FPR) was only 0.04% for each trisomy. In addition, for monosomy X (Turner syndrome), the sensitivity was only 95.8% and the false-positive rate was 0.14%. With the above parameters, NIPT is a screening test with very high accuracy. However, NIPT is still only a screening test and cannot replace a diagnostic test.