The United Kingdom government plans to implement mass scale population testing for SARS-CoV-2 infection using Lateral Flow Devices (LFDs), yet the devices’ sensitivity is unknown. A study published in the open access journal PLOS Biology by Alan McNally at University of Birmingham, UK, and colleagues suggests while LFDs are highly effective in identifying SARS-CoV-2 in individuals with high quantities of viral RNA present on the test swab, they are inaccurate at diagnosing infections in individuals with lower viral loads.