Systematic reviews of studies quantifying the accuracy of diagnostic tests and markers.

Systematic reviews of diagnostic accuracy studies allow calculation of pooled estimates of accuracy with increased precision and examination of differences in accuracy between tests or subgroups of studies. Recently, several advances have been made in the methods used in performing systematic reviews of diagnostic test accuracy studies, most notably in how to assess the methodological quality of primary diagnostic test accuracy studies by use of QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2) instrument and how to develop sound statistical models for metaanalysis of the paired measures of test accuracy (bivariate metaregression model of sensitivity and specificity). This article provides an overview of the different steps within a diagnostic systematic review and highlights these advances, illustrated with empirical data. The potential benefits of some recent developments in the areas of network metaanalysis and individual patient data metaanalysis for diagnostic tests are also discussed.