Systematic reviews of diagnostic tests and the development of QUADAS-3

Healthcare professionals often use diagnostic tests to identify the underlying cause of patients’ signs or symptoms. It is important that the clinical utility and diagnostic accuracy of these tests are evaluated by robust studies before they are recommended for use in clinical practice. This information is useful to healthcare decision makers who want to know whether the test will lead to health benefits, and whether it can correctly distinguish between people who have the target condition (the condition that the test aims to identify) and people who do not. Systematic reviews of diagnostic tests are a helpful resource for this information, as they summarise findings from primary studies to provide an overview of the impact of the diagnostic test on outcomes such as clinical utility and diagnostic test accuracy. Systematic reviews should include thorough risk of bias and applicability assessment, because a review of studies at high risk of bias or high applicability concerns may lead to misleading conclusions. QUADAS-2 is the most commonly used tool for quality assessment of diagnostic test accuracy studies in systematic reviews, however it was published in 2011 and was in need of an update. This thesis focuses on systematic reviews of diagnostic tests (chapters one-two) and the development of QUADAS-3: a revised tool for quality assessment of diagnostic studies (chapters 3-6).