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Table 3 Empirical results

From: First trimester screening for trisomy 21 in gestational week 8-10 by ADAM12-S as a maternal serum marker

  1 in 100 1 in 250
  FPR
(95% CI)
DR
(95% CI)
FPR
(95% CI)
DR
(95% CI)
(i) maternal age, PAPP-A & free B-hCG 2.9
(1.5, 4.2)
72.2
(65.7, 78.7)
9.4
(7.0, 11.8)
86.2
(79.0, 93.3)
(ii) maternal age, PAPP-A, free B-hCG & ADAM12-S 2.6
(1.3, 3.9)
73.7
(67.7, 79.6)
9.3
(7.0, 11.7)
87.3
(80.4, 94.2)
(iii) maternal age, PAPP-A, free B-hCG & NT 0.6
(0.1, 1.2)
71.1
(61.8, 80.5)
2.8
(1.5, 4.1)
83.7
(75.7, 91.8)
(iv) maternal age, PAPP-A, free B-hCG, NT & ADAM12-S 0.7
(0.1, 1.3)
71.1
(61.8, 80.5)
2.6
(1.4, 3.8)
87.7
(80.4, 94.9)
(v) maternal age, PAPP-A & ADAM12-S 2.5
(1.4, 3.7)
56.8
(50.1, 63.5)
9.2
(6.9, 11.4)
73.7
(63.6, 83.8)
(vi) maternal age, PAPPA, ADAM12-S & NT 1.4
(0.6, 2.3)
75.1
(67.2, 83.1)
3.5
(2.2, 4.9)
81.4
(75.3, 87.6)
  1. Results for a screening test including maternal age, PAPP-A and ADAM12-S, with and without NT. These results are empirical values, standardised to a reference maternal age population (UK 2000 to 2002). Detection rates and false-positive rates for fetal trisomy 21 at fixed risk cut-offs of 1 in 100 and 1 in 250 are given. Figures in brackets are 95% confidence intervals. Substantial decrease in DR when first trimester free B-hCG in (i) is replaced with ADAM12-S to give (v), with a negligible decrease in FPR.
  2. Substituting free B-hCG in the combined test (iii) for ADAM12-S to give (vi), gives a slightly higher DR and FPR at a risk cut-off of 1 in 100, and a slightly lower DR and higher FPR at a risk cut-off of 1 in 250.