The QUADAS（Quality Assessment of Diagnostic Accuracy Studies）tool, a quality assessment tool of diagnostic studies was developed in 2003, and thereafter the Cochrane Collaboration recommended QUADAS for use in systematic reviews of diagnostic accuracy. Following further revision, mainly by the GRADE（Grading of Recommendations Assessment, Development and Evaluation） working group, QUADAS－2 was released in 2011 （http://www.bris.ac.uk/quadas/）. With the permission of the original authors, Japanese language localization was undertaken and released on the MINDS website in April 2014（http://minds.jcqhc.or.jp）, and release on the QUADAS website is scheduled for May 2014.The original QUADAS tool includes 14 items assessing bias risk, applicability, and for reporting quality. The QUADAS－2 tool consists of 4 phases：1）summarization of the review question, 2）tailoring of the tool and the production of review－specific guidance, 3）construction of a flow diagram for the primary study, 4）assessment of bias and applicability. The last phase is applicable to 4 domains：patient selection, index test, reference standards, and flow and timing. Each domain is assessed according to bias risk using signalling questions of“yes,”“no,”or“unclear.”The first 3 domains are also assessed in terms of applicability. This tool will facilitate increased transparency in the rating of bias and improve applicability in the systematic review of diagnostic accuracy studies.