We review the medico-economic literature assessing the economic value of diagnostic tests. We first present the health technology assessment methods, as applied to generic health interventions. We then define our object of study, diagnostic and prognostic tests, and relate them to various definitions of personalized medicine. We then review the empirical assessments of diagnostic tests related to personalized medicine and of companion tests. We summarize systematic reviews which are not performing quantitative meta-analyses, but rather provide a descriptive synthesis of the results reviewed. We find no evidence that such tests perform better than more traditional approaches, such as pharmaceutical interventions. At the same time, there is a lot of heterogeneity in the cost per QALY (Quality-Adjusted Life Year) gained, so that some genetic testing procedures may perform better than non-genetic ones. Finally, we focus on imperfect tests and show how to optimize, from an economic perspective, their accuracy levels, and how to take accuracy levels into considerations when assessing their economic value.
