Prior to the ACT-Accelerator, few partnerships were convened in the diagnostics space to deliver on public health priorities. The ACT-A Diagnostics Pillar brought together more than 50 global health partners and civil society representatives with a common agenda. It has five working groups, each addressing various aspects of the diagnostic value chain to ensure that low-cost and high-quality diagnostic tools and resources are available globally. Agencies with expertise in a particular area lead these working groups. Each group draws members from an array of technical specialists, with civil society represented in each group.