Figure 4

Funnel plot for evaluation of publication bias in studies with in-house tests The funnel graph plots the log of the diagnostic odds ratio (DOR) against the standard error of the log of the DOR (an indicator of sample size). Each open circle represents each study in the meta-analysis. The line in the center indicates the summary DOR. In the absence of publication bias, the DOR estimates from smaller studies are expected to be scattered above and below the summary estimate, producing a triangular or funnel shape. The funnel plots appear asymmetric – smaller studies with low DOR estimates are missing – indicating a potential for publication bias. The Egger test for publication bias was statistically significant (p = 0.002) in the in-house test subgroup.