We review the medico-economic literature assessing the economic value of diagnostic and prognostic tests, with a focus on innovative and, more specifically, companion tests. Our analysis begins with a summary of systematic reviews that provide a descriptive synthesis of existing findings rather than conducting quantitative meta-analyses. These reviews reveal no consistent evidence that such tests outperform traditional approaches, such as pharmaceutical interventions. However, the cost-effectiveness of these tests, often measured in cost per QALY (Quality-Adjusted Life Year) gained, exhibits considerable heterogeneity. Notably, some genetic testing procedures may demonstrate superior performance compared to non-genetic alternatives. We then examine the economic implications of imperfect test features, exploring strategies to optimize their accuracy levels and integrating these considerations into the assessment of their economic value. Lastly, we review recent methodological and empirical studies employing these approaches, highlighting advancements in evaluating the economic impact of diagnostic and prognostic tests.
