Detecting clinically relevant diagnostic biomarkers, suitable for point-of-care detection, may facilitate rapid treatment and prevention of disease. However, medical diagnosis for which there are limited quantities of testable tissue or fluid, require point-of-care technologies with superior sensitivity and specificity. The purpose of this Editorial is to provide an overview of the Collection’s content, comprising original research into fluidics-based diagnostic platforms—specifically those made of paper or other low-cost materials, that can suitably operate with tiny sample volumes from mL to nL. In particular, we will focus on the clinical applications of such research, with potential uses in a number of fields including combating the COVID-19 pandemic for instance.