ADVANCEMENTS IN POINT-OF-CARE DIAGNOSTIC ASSAYS FOR NON-INVASIVE SAMPLES IN RESOURCE CONSTRAINED SETTINGS

Abstract

Diagnostic tools available in high-income countries are often not available in lower- and middle-income countries (LMICs) due to the requirement of highly trained workers and expensive equipment. The COVID-19 pandemic highlighted a significant need to self-test in the home to reduce transmission of disease. Many current diagnostics simply do not meet the needs of LMICs or a home environment. The result is a lack of access to reliable diagnostics or inadequate tools that are insensitive and miss early detection leading to increased mortality. The World Health Organization has developed a set of characteristics that make a diagnostic test suitable in LMICs, which focuses on affordability, sensitivity, specificity, user-friendly, rapid, equipment-free and delivery (ASSURED). Our research seeks to achieve these characteristics by developing diagnostic devices based on self-sampling methods and molecular-based approaches that are low-cost and improve early detection of disease. Specifically, we use non-invasive and low hazard samples (urine and interstitial fluid) in the developed devices and methods. Our results indicate that 1) volume controlled delivery of urine onto commercial dipstick pads can reduce user error to facilitate urine screening among untrained users, 2) urine self-sampling with our devices can be adopted to monitor changes more effectively in HE4 which is a biomarker for ovarian cancer reoccurrence, 3) interstitial fluid from self-sampling of skin can be used to provide early detection of the Lyme disease bacteria borrelia burgdorferi, and 4) short fragments of tuberculosis DNA in an easily obtained urine sample provides a simpler screen for this highly infectious airborne pathogen. Combined, these approaches provide a foundation for further LMIC and home-testing diagnostic development for several underserved diseases.