Table 3.

Detection rates of chromosomal anomalies and positive test ratios after combined first trimester screening (FTS), 2015

n = 34 796	Nuchal translucency	%	Combined FTS	%	Test positive %
Trisomy 21, n = 131	101/131	77	121/131	92	3.8
Trisomy 18, n = 43	30/43	70	36/43	84	0.5
Trisomy 13, n = 9	6/9	67	6/9	67
Triploidy, n = 10	3/10	30	10/10	100
Turner syndrome, n = 16	13/16	81	14/16	88
Total, n = 209	153/209	73	187/209	89	4.3