WP3: Development of new diagnostic methods

Remote analysis of sputum smears for mycobacterium tuberculosis quantification using digital crowdsourcing

Lara García Delgado, María Postigo, Daniel Cuadrado, Sara Gil-Casanova, Álvaro Martínez Martínez, María Linares, Paloma Merino, Manuel Gimo, Silvia Blanco, Quique Bassat, Andrés Santos, Alberto L. García- Basteiro, María J. Ledesma-Carbayo, Miguel A Luengo-Oroz


Worldwide, TB is one of the top 10 causes of death and the leading cause from a single infectious agent. Although the development and roll out of Xpert MTB/RIF has recently become a major breakthrough in the field of TB diagnosis, smear microscopy remains the most widely used method for TB diagnosis, especially in low- and middle-income countries. This research tests the feasibility of a crowdsourced approach to tuberculosis image analy- sis. In particular, we investigated whether anonymous volunteers with no prior experience would be able to count acid-fast bacilli in digitized images of sputum smears by playing an online game. Following this approach 1790 people identified the acid-fast bacilli present in 60 digitized images, the best overall performance was obtained with a specific number of combined analysis from different players and the performance was evaluated with the F1 score, sensitivity and positive predictive value, reaching values of 0.933, 0.968 and 0.91, respectively.