Towards point-of-care diagnostics of neglected tropical diseases using nucleic acid amplification tests

Neglected tropical diseases (NTDs) impose a substantial global burden, yet diagnostic innovation for these conditions has historically been lower than for other major infectious diseases. Addressing this diagnostic gap is a prerequisite for their elimination, as recognised by the World Health Organization (WHO). This critical review evaluates the current scope of point-of-care nucleic acid amplification tests (POC NAATs) through a systematic analysis of 39 studies. This is achieved via a breakdown of the nucleic acid amplification workflow and associated implementation barriers with a focus on operational feasibility rather than analytical metrics such as sensitivity and specificity. The reviewed publications showed several reoccurring themes such as simplified extraction methods, integrated workflows on platforms or devices, smartphone apps for interpretation, reducing cold-chain dependence, and electricity-independent workflows. However, several technical, analytical, and implementation barriers were also identified which hinder the transition from proof-of-concept prototypes to field-deployable tools that meet the criteria set up by the WHO for POC tests. The review showcases that a majority of current NAAT developments for NTDs do not yet fulfil the WHO criteria for POC application in resource-limited settings. Whilst there are opportunities for improvement as well as for repurposing NAAT platforms for other diseases, careful examination of all steps from sample collection to mature implementation in the field is required to achieve the aim set up by the WHO.