BACKGROUND: Diagnostics are essential for identifying and controlling diseases. However, limited access to diagnostics hinders public health efforts in many settings. Social innovation may provide a framework for expanding access to diagnostics in the global south. Here social innovation is defined as implementing a known public health tool via a novel, community-driven technique. MAIN BODY: In this article, we discuss three diverse cases that show the potential for using social innovation in diagnostics. The cases chosen for inclusion here demonstrate the importance of social innovation in diagnostics across different geographic, cultural, and health system contexts. They include malaria testing via schools in Malawi, cervical human papillomavirus (HPV) sample self-collection in Peru, and crowdsourcing human immunodeficiency virus (HIV) testing in China. For each case, we present the public health problem and the impact of using social innovation to increase accessibility of diagnostics. We discuss implications of each diagnostic approach and the importance of social innovation in creating these potential solutions. We argue that social innovation is useful in improving the delivery of essential diagnostic tools in low- and middle-income countries. CONCLUSIONS: Interventions in Malawi, Peru, and China suggest social innovation increases uptake of diagnostics. The same tools and principles utilized in these cases can be adapted for use in other contexts. Such diagnostic innovations may help improve identification of and linkage to care for many diseases. The approach presents a unique opportunity to better address public health issues and increase accessibility in LMIC health systems.