Frontomaxillary Facial Angle Measurement in Screening for Trisomy 18 at 11 + 0 to 13 + 6 Weeks of Pregnancy: A Double-Centre Study

Table 2

Model 1—based on the maternal age, first trimester biochemistry test, and NT measurement, in four predefined trisomy 18 risk cut-off points.

Risk	1 : 300	1 : 200	1 : 100	1 : 50
DR (%)	85	85	83	80
FPR (%)	0.5	0.5	0.4	0.3
PPV (%)	57.8	65.0	73.7	66.7
NPV (%)	99.7	99.7	99.8	99.8
LR+	55.15	73.66	111.06	80.0
LR−	0.14	0.13	0.067	0.067
𝑃 value	<0.0001	<0.0001	=0.0014	=0.0003