The impact of clinical metagenomic testing on patient management: facts versus fantasy.

Clinical metagenomic testing by agnostic, unbiased next-generation sequencing is a diagnostic approach with the broad-based capacity to detect all known and novel pathogens in a single assay. After the discovery of this potentially transformative method decades ago, the availability of clinical metagenomic testing in the daily practice of the infectious disease specialist is accelerating. Prospective metagenomic studies have supplemented the substantial existing body of retrospective, exploratory literature, and these reports offer us a glimpse into the real-world use of clinical metagenomic testing for the diagnosis of infections in patients. In this Review, we examine the evidence collected from the prospective reports published to date, focusing on their impact on patient management, treatment, and outcomes.