2.

Detection rates (sensitivity) at a 5% false positive rate for the nine selected test strategies. Each circle represents the summary sensitivity for a test strategy and the size of each circle is proportional to the number of Down's cases. The estimates are shown with 95% confidence intervals. The test strategies are ordered on the plot according to decreasing detection rate. The number of studies, cases and women included for each test strategy are shown on the horizontal axis.

A = Age, PlGF, PAPP‐A and free ßhCG; B = Age, PAPP‐A, free ßhCG and AFP; C = Age, ADAM 12, PAPP‐A and free ßhCG; D = Age, PAPP‐A and free ßhCG ; E = Age, PAPP‐A; F = PAPP‐A; G = Age, free ßhCG and AFP ; H = Age, free ßhCG; I = Free ßhCG