Objective: Interest in evidence-based diagnosis is growing rapidly as diagnostic and screening techniques proliferate. In this article we provide an overview of systematic reviews of diagnostic performance and discuss in detail statistical methods for the most common variant of the problem: meta-analysis of studies in which a pair of estimates of sensitivity and specificity is reported. The need to account for possible variations in threshold for test positivity across studies led to the formulation of the Summary ROC (SROC) curve method. We discuss graphical and model-based ways to estimate, summarize, and compare SROC curves, and we present an example from a meta-analysis of data on techniques for staging cervical cancer. We also present a brief survey of the methodologic literature for addressing heterogeneity, correlated data, multiple thresholds per study, and systematic reviews of ROC studies. We conclude with a discussion of the significant methodologic challenges that continue to face investigators in this area of diagnostic medicine research.
Conclusion: Systematic reviews of diagnostic performance are a rigorous approach to examining and synthesizing evidence in the evaluation of diagnostic and screening tests. The information from such reviews is needed by clinicians, health policy makers, researchers in diagnostic medicine, developers of diagnostic techniques, and the general public. However, despite progress in study quality and reporting and in methodologic development, major challenges confront investigators undertaking these reviews.