Aligning diagnostics to the point-of-care: lessons for innovators, evaluators and decision-makers from tuberculosis and HIV

Equivocal diagnostics: Making a 'good' point-of-care test for elimination in global health

What is a diagnostic test for? We might assume the answer to this question is straightforward. A good test would help identify what disease someone suffers from, assist health providers to determine the correct course of treatment and/or enable public health authorities to know and intervene in health at the level of the population. In this article, we show that what a specific diagnostic test is for, the value it holds for different actors, and what makes it good, or not, is often far from settled. We tell the story of the development and design of a rapid antibody test for onchocerciasis, or river blindness, tracking multiple iterations of the device through three configurational moments in the framing of onchocerciasis disease and reshaping of the global health innovation ecosystem. Efforts to build that ecosystem for diagnostics are often premised on the notion that public health needs for diagnostics are pre-given and stable; the challenge is seen to be how to incentivize investment and find a customer base for diagnostics in under-resourced settings. By contrast, we show that for any disease, diagnostic needs are both multiple and constantly in flux, and are unlikely to be met by a single, stand-alone product. In the case of the onchocerciasis Ov-16 rapid test, the failure to recognize and address the multiplicity and instability of diagnostic needs in the innovation process resulted in the development of a rapid point of care test that might be manufactured, procured and used, but is unloved by public health experts and commercial manufacturers alike. The equivocal value of the onchocerciasis rapid test, we suggest, reveals the inadequacy of the current global health innovation ecosystem for developing diagnostic 'goods'.

A Review of the Current Status of G6PD Deficiency Testing to Guide Radical Cure Treatment for Vivax Malaria

Plasmodium vivax malaria continues to cause a significant burden of disease in the Asia-Pacific, the Horn of Africa, and the Americas. In addition to schizontocidal treatment, the 8-aminoquinoline drugs are crucial for the complete removal of the parasite from the human host (radical cure). While well tolerated in most recipients, 8-aminoquinolines can cause severe haemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficient patients. G6PD deficiency is one of the most common enzymopathies worldwide; therefore, the WHO recommends routine testing to guide 8-aminoquinoline based treatment for vivax malaria whenever possible. In practice, this is not yet implemented in most malaria endemic countries. This review provides an update of the characteristics of the most used G6PD diagnostics. We describe the current state of policy and implementation of routine point-of-care G6PD testing in malaria endemic countries and highlight key knowledge gaps that hinder broader implementation. Identified challenges include optimal training of health facility staff on point-of-care diagnostics, quality control of novel G6PD diagnostics, and culturally appropriate information and communication with affected communities around G6PD deficiency and implications for treatment.

The (in)visibility of misdiagnosis in point-of-care HIV testing in Zimbabwe

There is a global trend to introduce point-of-care diagnostic tests, enabling healthcare workers at any level to test, provide results, and initiate immediate treatment if necessary. This article explores how healthcare workers conducting rapid HIV tests - in contexts of limited external quality assurance mechanisms - ascertain the accuracy of their test results. Drawing on interview data and participant observations from health facilities in Zimbabwe, we open the black box of misdiagnosis (in)visibility and reveal a range of proxies and markers that HIV testers draw on to develop certainty, or question, the reliability of their diagnostic classifications.

Reimagining the status quo: How close are we to rapid sputum-free tuberculosis diagnostics for all?

Rapid, accurate, sputum-free tests for tuberculosis (TB) triage and confirmation are urgently needed to close the widening diagnostic gap. We summarise key technologies and review programmatic, systems, and resource issues that could affect the impact of diagnostics. Mid-to-early-stage technologies like artificial intelligence-based automated digital chest X-radiography and capillary blood point-of-care assays are particularly promising. Pitfalls in the diagnostic pipeline, included a lack of community-based tools. We outline how these technologies may complement one another within the context of the TB care cascade, help overturn current paradigms (eg, reducing syndromic triage reliance, permitting subclinical TB to be diagnosed), and expand options for extra-pulmonary TB. We review challenges such as the difficulty of detecting paucibacillary TB and the limitations of current reference standards, and discuss how researchers and developers can better design and evaluate assays to optimise programmatic uptake. Finally, we outline how leveraging the urgency and innovation applied to COVID-19 is critical to improving TB patients' diagnostic quality-of-care.

Understanding complexities in the uptake of indigenously developed rapid point-of-care diagnostics for containment of antimicrobial resistance in India

A good point-of-care diagnostic test holds a promise to reduce inappropriate use of antibiotics by enabling early detection of the pathogen and facilitating rapid testing of antimicrobial susceptibility. India has taken many initiatives in the recent past to augment the development and deployment of diagnostics in Indian health care system. Funding opportunities to promote innovation in diagnostics development were started in early 2000s through various ministries and departments. India released National Essential Diagnostics List which enlists essential tests and there is now Free Diagnostics Service Initiative of Government of India under National Health Mission that mandates to provide all essential tests free of cost. We wanted to understand how these initiatives have impacted the diagnostics that could be of use in containment of antimicrobial resistance (AMR) and whether there is a smooth process for bringing indigenously developed products relevant to AMR into the healthcare system. We conducted a longitudinal survey (January 2019 and January 2021) to understand the availability of market ready indigenous rapid diagnostics for AMR in the country and their progress towards introduction in the private market or uptake in healthcare system. We found that many innovators and developers are working towards development of rapid tests that can be useful in the containment of AMR in India. While there are many promising diagnostics on the horizon, the pathway for uptake of indigenously developed diagnostics in healthcare system remains disjointed and needs to be harmonised for the investments made towards development to translate as tangible gains. Since most of these efforts are government funded, it is incumbent upon the government to also provide a seamless pathway to make these diagnostics available in health care system. In absence of this guidance, most of these diagnostics will sit with the innovators/developers and will never be used for the purpose they were intended to serve.