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Point-of-Care Testing for Infectious Diseases: Diversity, Complexity, and Barriers in Low- And Middle-Income Countries

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      Abstract

      Madhukar Pai and colleagues discuss a framework for envisioning how point-of-care testing can be applied to infectious diseases in low- and middle-income countries.

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      Most cited references 35

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      Feasibility, diagnostic accuracy, and effectiveness of decentralised use of the Xpert MTB/RIF test for diagnosis of tuberculosis and multidrug resistance: a multicentre implementation study

      Summary Background The Xpert MTB/RIF test (Cepheid, Sunnyvale, CA, USA) can detect tuberculosis and its multidrug-resistant form with very high sensitivity and specificity in controlled studies, but no performance data exist from district and subdistrict health facilities in tuberculosis-endemic countries. We aimed to assess operational feasibility, accuracy, and effectiveness of implementation in such settings. Methods We assessed adults (≥18 years) with suspected tuberculosis or multidrug-resistant tuberculosis consecutively presenting with cough lasting at least 2 weeks to urban health centres in South Africa, Peru, and India, drug-resistance screening facilities in Azerbaijan and the Philippines, and an emergency room in Uganda. Patients were excluded from the main analyses if their second sputum sample was collected more than 1 week after the first sample, or if no valid reference standard or MTB/RIF test was available. We compared one-off direct MTB/RIF testing in nine microscopy laboratories adjacent to study sites with 2–3 sputum smears and 1–3 cultures, dependent on site, and drug-susceptibility testing. We assessed indicators of robustness including indeterminate rate and between-site performance, and compared time to detection, reporting, and treatment, and patient dropouts for the techniques used. Findings We enrolled 6648 participants between Aug 11, 2009, and June 26, 2010. One-off MTB/RIF testing detected 933 (90·3%) of 1033 culture-confirmed cases of tuberculosis, compared with 699 (67·1%) of 1041 for microscopy. MTB/RIF test sensitivity was 76·9% in smear-negative, culture-positive patients (296 of 385 samples), and 99·0% specific (2846 of 2876 non-tuberculosis samples). MTB/RIF test sensitivity for rifampicin resistance was 94·4% (236 of 250) and specificity was 98·3% (796 of 810). Unlike microscopy, MTB/RIF test sensitivity was not significantly lower in patients with HIV co-infection. Median time to detection of tuberculosis for the MTB/RIF test was 0 days (IQR 0–1), compared with 1 day (0–1) for microscopy, 30 days (23–43) for solid culture, and 16 days (13–21) for liquid culture. Median time to detection of resistance was 20 days (10–26) for line-probe assay and 106 days (30–124) for conventional drug-susceptibility testing. Use of the MTB/RIF test reduced median time to treatment for smear-negative tuberculosis from 56 days (39–81) to 5 days (2–8). The indeterminate rate of MTB/RIF testing was 2·4% (126 of 5321 samples) compared with 4·6% (441 of 9690) for cultures. Interpretation The MTB/RIF test can effectively be used in low-resource settings to simplify patients' access to early and accurate diagnosis, thereby potentially decreasing morbidity associated with diagnostic delay, dropout and mistreatment. Funding Foundation for Innovative New Diagnostics, Bill & Melinda Gates Foundation, European and Developing Countries Clinical Trials Partnership (TA2007.40200.009), Wellcome Trust (085251/B/08/Z), and UK Department for International Development.
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        Point-of-care diagnostics for global health.

        Biomedical engineers have traditionally developed technologies in response to the needs of the developed world's medical community. As a result, the diagnostic systems on which they have worked have met the requirements of well-funded laboratories in highly regulated and quality-assessed environments. However, such approaches do not address the needs of the majority of the world's people afflicted with infectious diseases, who have, at best, access to poorly resourced health care facilities with almost no supporting clinical laboratory infrastructure. A major challenge for the biomedical engineering community is to develop diagnostic tests to meet the needs of these people, the majority of whom are in the developing world. We here review the context in which the diagnostics must operate, some of the appropriate diagnostic technologies already in distribution, and some emerging technologies that promise to address this challenge. However, there is much room for innovation, adaptation, and cost reduction before these technologies can impact health care in the developing world.
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          Point-of-care nucleic acid testing for infectious diseases.

          Nucleic acid testing for infectious diseases at the point of care is beginning to enter clinical practice in developed and developing countries; especially for applications requiring fast turnaround times, and in settings where a centralized laboratory approach faces limitations. Current systems for clinical diagnostic applications are mainly PCR-based, can only be used in hospitals, and are still relatively complex and expensive. Integrating sample preparation with nucleic acid amplification and detection in a cost-effective, robust, and user-friendly format remains challenging. This review describes recent technical advances that might be able to address these limitations, with a focus on isothermal nucleic acid amplification methods. It briefly discusses selected applications related to the diagnosis and management of tuberculosis, HIV, and perinatal and nosocomial infections. Copyright © 2011. Published by Elsevier Ltd.
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            Author and article information

            Affiliations
            [1 ]Division of Clinical Epidemiology, Department of Medicine, McGill University, Montreal, Canada
            [2 ]Respiratory Epidemiology & Clinical Research Unit, Montreal Chest Institute, Montreal, Canada
            [3 ]Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
            [4 ]Department of Health, Ethics and Society/Caphri, Faculty of Health, Medicine and Life Sciences, Maastricht University, The Netherlands
            [5 ]Department of Epidemiology & Biostatistics, McGill University, Montreal, Canada
            Author notes

            No financial or industry conflicts. MP serves as a consultant for the Bill & Melinda Gates Foundation. BMGF had no involvement in this manuscript. NPP is an Academic Editor with PLOS ONE. MP is on the editorial boards of PLOS ONE and PLOS Medicine. The other authors have declared that no competing interests exist.

            Wrote the first draft of the manuscript: NPP MP. Contributed to the writing of the manuscript: CV CD NE. ICMJE criteria for authorship read and met: NPP CV CD NE MP. Agree with manuscript results and conclusions: NPP CV CD NE MP.

            Provenance: Not commissioned; externally peer reviewed.

            The Policy Forum allows health policy makers around the world to discuss challenges and opportunities for improving health care in their societies.

            Journal
            PLoS Med
            PLoS Med
            PLoS
            plosmed
            PLoS Medicine
            Public Library of Science (San Francisco, USA )
            1549-1277
            1549-1676
            September 2012
            September 2012
            4 September 2012
            : 9
            : 9
            3433407
            22973183
            PMEDICINE-D-12-01227
            10.1371/journal.pmed.1001306

            This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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            Pages: 7
            Funding
            NPP and MP are supported by the Bill & Melinda Gates Foundation (grant OPP1061487), Grand Challenges Canada (Canadian Rising Stars in Global Health grants) and Canadian Institutes of Health Research (grants MOP-89918 & HBF-103210). MP is also supported by the European and Developing Countries Clinical Trials Partnership (EDCTP - TBNEAT grant) and the Fonds de recherche du Québec – Santé (FRQS). The funders had no role in the analysis of data and decision to publish.
            Categories
            Policy Forum
            Medicine
            Diagnostic Medicine
            Test Evaluation
            Global Health
            Infectious Diseases
            Infectious Disease Control
            Neglected Tropical Diseases

            Medicine

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