Diagnostic infrastructuring: Biomarkers, pharmaceutical marketing and governance in Taiwan.

This ethnographic study examines the role of pharmaceutical companies in the era of precision medicine. Focusing on PD-L1 biomarker testing for cancer immunotherapy under Taiwan's National Health Insurance reimbursement policy, we trace how these diagnostics are introduced, adopted, and governed within the policy regime that frames therapeutic access. We propose the concept of "diagnostic infrastructuring" to describe how corporate entities act as "infrastructural architects," actively remodeling material platforms and clinical practices to facilitate the routinization of biomarker tests. Extending Sergio Sismondo's discourse on "assemblage marketing," this study reveals a shift toward material and practice governance. In this model, firms mobilize technical objects, standardize practices, and negotiate interpretive discretion and leniency to align with rigid policy frameworks, thereby bridging infrastructural gaps. By governing diagnostic routines, companies embed commercial interests directly into the clinical and reimbursement infrastructures of precision medicine. Ultimately, this industry-driven infrastructuring illuminates an evolving political economy where the capacity to deliver precision medicine is contingent upon the power to configure biomarker diagnostic practice.