Carrying a mismatch repair gene mutation substantially increases risk of colorectal, endometrial and other cancers (Lynch syndrome). Several criteria have been developed to triage colorectal cancer cases for genetic testing, and several statistical prediction tools have been developed to provide probability of having a mismatch repair gene mutation. We have systematically reviewed each of these criteria and prediction tools for their utility, and conducted a meta-analysis to summarise their accuracy. The prediction tools had a high degree of accuracy and were generally equivalent. This review will be of primary interest to clinical services specialising in the detection of Lynch syndrome. (By Dr Aung Ko Win, http://jmg.bmj.com/content/early/2013/08/16/jmedgenet-2013-101803 )