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Indian Journal of Medical Microbiology
Medknow Publications on behalf of Indian Association of Medical Microbiology
ISSN: 0255-0857 EISSN: 1998-3646
Vol. 28, Num. 1, 2010, pp. 2-4

Indian Journal of Medical Microbiology, Vol. 28, No. 1, January-March, 2010, pp. 2-4

Guest Editorial

Evidence-based diagnosis of tuberculosis: Resources for the medical microbiologist

Department of Epidemiology and Biostatistics (JM & MP), McGill University, Respiratory Epidemiology and Clinical Research Unit (JM & MP), Montreal Chest Institute, Montreal, Canada

Correspondence Address: *Department of Epidemiology and Biostatistics (JM & MP), McGill University, Respiratory Epidemiology and Clinical Research Unit (JM & MP), Montreal Chest Institute, Montreal, Canada, madhukar.pai@mcgill.ca

Code Number: mb10002

PMID: 20061754

DOI: 10.4103/0255-0857.58719

Evidence-based clinical practice (EBCP) is a well-accepted approach in clinical medicine. The goal of EBCP is to successfully apply objective research evidence to enhance clinical practice and improve patient outcomes. EBCP requires us to base our clinical decisions on the best available evidence regarding a diagnostic, an intervention or a preventive measure. Evidence-based diagnosis is an integral part of EBCP and the rational use and application of diagnostic tests must be directed by high-quality evidence to determine the real impact of diagnostic tests on clinical practice and patient management. Evidence-based diagnosis is slowly gaining prominence. The Cochrane Collaboration, for example, recently began publishing systematic reviews on diagnostic test accuracy in the Cochrane Library. [1] There are several books devoted to evidence-based diagnosis [2],[3] and many health agencies, including the World Health Organization (WHO), now require the use of evidence-based, transparent approaches such as GRADE for guideline and policy development on diagnostics. [4]

Given the global importance of tuberculosis (TB), a disease that affects millions of people across the world, it is imperative that the basic principles of EBCP apply to TB just as they apply to every other disease. TB diagnosis and treatment needs to be evidence based and policies and guidelines on TB must take into account the best evidence that is available. Otherwise, resources will be wasted and TB patients will not receive the best international standard of TB care. [5] This is particularly true for diagnosis because many new TB diagnostic tests are in development and several are already entering the market. [6],[7] These new tools must be adequately investigated and validated before they can be routinely and widely used. Robust evidence is also necessary to inform policies and guidelines on TB diagnostics. Lastly, misdiagnosis of TB is common and often results in poor outcomes for TB patients. [8] We need to ask the questions: Why should these tests be used by national TB control programs and which tests are likely to have the biggest impact on improving outcomes in TB patients?

High-quality evidence on TB diagnostics is critical for the development of evidence-based policies on TB diagnosis and, ultimately, for effective control of the global TB epidemic. While primary diagnostic trials are needed to generate data on test accuracy (e.g. sensitivity and specificity), performance and impact in field conditions, systematic reviews provide the best synthesis of current evidence on any given diagnostic test. In the past few years, more than 35 systematic reviews have been published on various TB diagnostic tests and these reviews have formed the evidence base for TB diagnosis. [9] Systematic reviews have provided useful clinical insights and have informed policies and guidelines on TB diagnosis. They have also generated new research questions and priorities. [9]

The Stop TB Partnership (STP) was established in 1998 to work towards the goal of eliminating TB as a public health problem. The STP has three working groups focused on the most active areas of current development: Drugs, vaccines and diagnostics. The STP′s New Diagnostics Working Group (NDWG) was established in 2001 as one of the core working groups within the partnership. The NDWG plays a key role by coordinating and facilitating the development, evaluation and implementation of new and improved TB diagnostics in a scientifically acceptable, evidence-based and timely manner by linking together stakeholders involved in the diagnostics development and evaluation pathway. The mission of the NDWG is to advocate and implement research and/or operational activities in pursuit of the development and implementation of TB diagnostic tools and to collaborate with other elements of the partnership so as to create synergy and add value to actions taken in pursuit of the aims of the partnership. The NDWG has a large membership spread across the world. Anyone interested in TB diagnosis can join the NDWG as a member with no fee requirements ( http://www.stoptb.org/wg/new_diagnostics/ ).

Recognising the need for disseminating information about the evidence base for TB diagnosis, the NDWG recently launched a new website resource called Evidence-based Tuberculosis Diagnosis, available at: http://www.tbevidence.org [Figure - 1]. [10] Several agencies, groups and individuals contributed to the development of this comprehensive resource. These include the WHO, the Special Programme for Research and Training in Tropical Diseases (TDR), Foundation for Innovative New Diagnostics (FIND), the Global Laboratory Initiative, the Francis J Curry National TB Centre, McGill University and the Public Health Agency of Canada.

This website is now the most comprehensive single source of evidence syntheses, policies, guidelines and research agendas on TB diagnosis. It provides reference to all published systematic reviews on TB diagnostics (grouped by type of test or platform), access to all the relevant policies (including all the WHO policies on TB diagnostics), guidelines and research agendas on TB diagnosis as well as numerous reports, monographs, algorithms, training modules and slide presentations on TB diagnostics. Videos and images of TB diagnostic tests are also available. A scientific blueprint for new TB diagnostics development was launched in 2009 and can be downloaded from the website.

The website has many resources that are of value to microbiologists and laboratory professionals working on TB. It provides detailed guidance on how to conduct and report high-quality diagnostic research on TB, guidance on how to perform systematic reviews of diagnostics and tools on guidelines development and documents on the improvement of laboratory quality, biosafety and practice. These resources are highly relevant, given the poor quality of existing TB diagnostic accuracy studies. [11] Up-to-date information on the current TB diagnostics pipeline is provided along with standard operating procedures and package inserts for several tests (commercial as well as non-commercial). Listings are provided for specimen banks, databases of resistance mutations, reports on biomarkers, gene sequences and microarray patterns in addition to a comprehensive collection of links to related TB websites.

A large collection of training materials is available via the website, including resources on TB biosafety, good laboratory practice, smear microscopy, culture, tuberculin skin tests and interferon-gamma release assays. All information is provided as open access, with no registration or fee requirements. The website is not funded or supported by any company or commercial organisation. New material is constantly being added and updated to ensure that TB clinicians, researchers and laboratory professionals can keep up-to-date with the world of TB diagnostics at a single site.

Since the launch of the website in August 2009, the website has received over 12,000 visits and more than 40,000 page views from individuals in over 150 countries. The website has been featured in several websites and journals, including WHO, Stop TB Partnership, UNAIDS, TDR, FIND, TropIKA, American Thoracic Society (ATS), Infectious Diseases Society of America (IDSA), Cochrane Collaboration, Association of Public Health Laboratories (APHL) and Public Library of Science (PLoS). Clearly, this new website resource is meeting a long-standing need for a single portal that compiles all critical evidence on TB diagnosis along with relevant policies and guidelines for clinicians, laboratory professionals, health professionals and policy makers.

References

1.Leeflang MM, Deeks JJ, Gatsonis C, Bossuyt PM; Cochrane Diagnostic Test Accuracy Working Group. Systematic reviews of diagnostic test accuracy. Ann Intern Med 2008;149:889-97.  Back to cited text no. 1  [PUBMED]  [FULLTEXT]
2.Newman TB, Kohn MA. Evidence-based diagnosis. New York, USA: Cambridge University Press; 2009. p. 1-295.  Back to cited text no. 2    
3.Knottnerus JA, Buntinx F. The evidence base of clinical diagnosis: Theory and methods of diagnostic research. 2 nd ed. New Jersey, USA: Wiley Blackwell and BMJ Books; 2008. p. 1-320.  Back to cited text no. 3    
4.Schόnemann HJ, Oxman AD, Brozek J, Glasziou P, Jaeschke R, Vist GE, et al. Grading quality of evidence and strength of recommendations for diagnostic tests and strategies. BMJ 2008;336:1106-10.  Back to cited text no. 4    
5.Hopewell PC, Pai M, Maher D, Uplekar M, Raviglione MC. International standards for tuberculosis care. Lancet Infect Dis 2006;6:710-25.  Back to cited text no. 5    
6.Pai M, O'Brien R. New diagnostics for latent and active tuberculosis: State of the art and future prospects. Semin Respir Crit Care Med 2008;29:560-8.  Back to cited text no. 6    
7.Pai M, Minion J, Sohn H, Zwerling A, Perkins MD. Novel and improved technologies for tuberculosis diagnosis: Progress and challenges. Clin Chest Med 2009;30:701-16.  Back to cited text no. 7    
8.Davies PD, Pai M. The diagnosis and misdiagnosis of tuberculosis. Int J Tuberc Lung Dis 2008;12:1226-34.  Back to cited text no. 8    
9.Pai M, Ramsay A, O'Brien R. Evidence-based tuberculosis diagnosis. PLoS Med 2008;5: E156.  Back to cited text no. 9    
10.Pai M, Ramsay A, O'Brien R. Comprehensive new resource for evidence-based TB diagnosis. Exp Rev Mol Diagn 2009;9:637-9.  Back to cited text no. 10    
11.Fontela PS, Pai NP, Schiller I, Dendukuri N, Ramsay A, Pai M. Quality and Reporting of Diagnostic Accuracy Studies in TB, HIV and Malaria: Evaluation Using QUADAS and STARD Standards. PLoS One 2009; 4: E7753.  Back to cited text no. 11    

Copyright 2010 - Indian Journal of Medical Microbiology


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