Fig. 3From: Clinical performance of non-invasive prenatal served as a first-tier screening test for trisomy 21, 18, 13 and sex chromosome aneuploidy in a pilot city in ChinaThe relationship between FC%Y and FC%T between true-positive and false-positive samples. True-positive samples are shown as black spots, false-positive samples as red circles. T21 cases: dot; T18 cases: quadrate; T13 cases: triangleFC%: Fetal DNA concentration, FC%Y: Fetal DNA concentration calculated by Y chromosome, FC%T: Fetal DNA concentration calculated by the proportion of triploidBack to article page