A new audio-based COVID-19 screening test that analyzes the sound of a cough and only requires a smartphone was found to correctly detect COVID-19 in 92% of people with infection.

ResApp Health’s novel COVID screening test uses machine learning to analyze the sound of a patient’s cough. ResApp’s novel COVID test was explored in a clinical trial in which 741 patients (of which 446 were found to be COVID-19 positive) were recruited in the United States and India.

ResApp will position this as a non-invasive, instant, smartphone only screening test to rule out COVID-19 and be used prior to a rapid antigen (RAT) or PCR test.

In the trial, the test achieved a sensitivity of 92% (better than real-world data on rapid antigen tests[1],[2]) and a specificity of 80%. The combination of high sensitivity and 80% specificity results in 8 out of 10 people without COVID-19 being correctly screened as negative and not requiring a follow-on rapid antigen or PCR test.

“The scale of this pandemic and the likely evolution to an endemic disease means we need more scalable diagnostic tools that can balance our current over-reliance on rapid antigen and PCR tests,” says Professor Catherine Bennett, chair of Epidemiology at Deakin University, and a member of ResApp’s COVID-19 Scientific Advisory Board. “By rapidly ruling out COVID-19, ResApp’s COVID-19 test would significantly reduce the number of rapid antigen and PCR tests required, while still maintaining the disease surveillance needed to manage the continued impact of COVID-19. The simplicity, ease of use and unlimited scalability of ResApp’s test will be welcomed by public health officials around the world.”

The performance of the algorithm was obtained using K-fold cross-validation to provide an estimate of performance on unseen data. ResApp intends to submit the results for publication in a peer-reviewed journal.

The entire test and results take less than 30 seconds. The test also has unlimited scalability, no supply chain or distribution issues, and none of the environmental impacts of rapid antigen tests.

ResApp will target use in settings where frequent COVID-19 testing is required, such as employee, healthcare worker and student screening, travel, sports, entertainment, and aged care.

“This non-invasive, smartphone test will offer a unique opportunity to provide a rule-out screening test for COVID-19 at scale across the world, delivering huge savings to government, insurers and the public as well as significantly reducing the environmental impact of rapid antigen and PCR tests,” says Tony Keating, CEO and Managing Director of ResApp. “These results also build our confidence in the development of patient management and monitoring tools for COVID-19 and expanding our research into long-COVID.”


[1] Dinnes J., et al. (2021). Rapid, point-of-care antigen and molecular-based tests for diagnosis of SARS-CoV-2 infection. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.CD013705.pub2

[2] Hayer J., Kasapic D. and Zemmrich, C. (2021). Real-world clinical performance of commercial SARS-CoV-2 rapid antigen tests in suspected COVID-19: A systematic meta-analysis of available data as of November 20, 2020. International Journal of Infectious Diseases, 108, 592-602. https://doi.org/10.1016/j.ijid.2021.05.029