The accuracy and usability of point-of-use fluoride biosensors: a field study in Nakuru County, Kenya

Abstract Geogenic fluoride contaminates the water of tens of millions of people. However, many are unaware of the fluoride content due in part to shortcomings of detection methods. Biosensor tests are a relatively new approach to water quality testing that address many of these shortcomings but have never been tested by non-experts. We therefore sought to assess the accuracy and usability of a point-of-use fluoride biosensor using surveys and field tests in Nakuru County, Kenya. The biosensor tests accurately classified elevated fluoride (≥ 1.5 ppm) in 89.5% of the 57 samples tested. Usability was also high, with all participants able to use the test and all but one sample correctly interpreted. These data suggest that biosensor tests can provide accurate, meaningful water quality data to help non-experts make decisions about the water they consume. Further scaling of these technologies could provide new approaches to track global progress towards Sustainable Development Goal 6.