Figure 6.
Per-vessel funnel plots with contour for assessment of publication bias in diagnostic parameters (A, sensitivity; B, specificity; C, positive predictive value (PPV); and D, negative predictive value (NPV)). Areas in white, orange, and red represent <90%, 95–99%, and >99% confidence levels for publication bias. P-values are derived from Egger's regression (α = 0.05) and represent the likelihood of a study result at least this large given the null hypothesis to be true (H0 = No publication bias). PPV is likely subject to publication bias (P = 0.02).