|Year : 2007 | Volume
| Issue : 2 | Page : 89-92
International standards for tuberculosis care: Relevance and implications for laboratory professionals
M Pai1, P Daley2, PC Hopewell3
1 Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, H3A 1A2, Canada
2 Infectious Disease Training and Research Center, Christian Medical College, Vellore - 632004, India
3 Francis J Curry National Tuberculosis Center, Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California, San Francisco, CA 94110, USA
Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, H3A 1A2
Source of Support: None, Conflict of Interest: None
On World Tuberculosis (TB) Day 2006, the International Standards for Tuberculosis Care (ISTC) was officially released and widely endorsed by several agencies and organizations. The ISTC release was the culmination of a year long global effort to develop and set internationally acceptable, evidence-based standards for tuberculosis care. The ISTC describes a widely endorsed level of care that all practitioners, public and private, should seek to achieve in managing individuals who have or are suspected of having, TB and is intended to facilitate the effective engagement of all healthcare providers in delivering high quality care for patients of all ages, including those with smear-positive, smear-negative and extra-pulmonary TB, TB caused by drug-resistant Mycobacterium tuberculosis and TB/HIV coinfection. In this article, we present the ISTC, with a special focus on the diagnostic standards and describe their implications and relevance for laboratory professionals in India and worldwide. Laboratory professionals play a critical role in ensuring that all the standards are actually met by providing high quality laboratory services for smear microscopy, culture and drug susceptibility testing and other services such as testing for HIV infection. In fact, if the ISTC is widely followed, it can be expected that there will be a greater need and demand for quality assured laboratory services and this will have obvious implications for all laboratories in terms of work load, requirement for resources and trained personnel and organization of quality assurance systems.
Keywords: Laboratory quality, standards, tuberculosis
|How to cite this article:|
Pai M, Daley P, Hopewell P C. International standards for tuberculosis care: Relevance and implications for laboratory professionals. Indian J Med Microbiol 2007;25:89-92
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Pai M, Daley P, Hopewell P C. International standards for tuberculosis care: Relevance and implications for laboratory professionals. Indian J Med Microbiol [serial online] 2007 [cited 2021 Jan 25];25:89-92. Available from: https://www.ijmm.org/text.asp?2007/25/2/89/32712
On world tuberculosis (TB) day 2006, the International Standards for Tuberculosis Care (ISTC) was officially released,  and subsequently published in a condensed form in the Lancet Infectious Diseases.  Since its release, the ISTC has been endorsed by more than 30 international and national agencies and organizations, including the World Health Organization (WHO), the Stop TB Partnership, the International Union against TB and Lung Disease (IUATLD), the American Thoracic Society (ATS), the US Centres for Disease Control and Prevention (CDC), Canadian Tuberculosis Committee and the World Care Council. In India, the ISTC has been endorsed by the Indian Medical Association (IMA) and has been incorporated into training materials of the Revised National Tuberculosis Control Programme (RNTCP).
What is the rationale for the ISTC? Part of the reason for failing to bring about a more rapid reduction in TB incidence worldwide is the lack of effective involvement of all practitioners, public and private, in the provision of high quality TB care. ,, While healthcare providers who work within national TB programs (such as the RNTCP) are trained and are expected to have adopted proper diagnosis, treatment and public health practices, the same is clearly not true for non-program providers.  Studies of the performance of the private healthcare sector conducted in several different parts of the world, including India, demonstrate that poor quality care is common.  The recent emergence of extensively drug-resistant TB (XDR-TB) is a sign that proper standards of TB care are far from being universally applied. 
India has a large private healthcare sector and a large number of TB patients in India are managed by providers outside the RNTCP system.  Studies from India have shown that healthcare providers, in particular those who work in the private healthcare sector, often deviate from the standard, internationally recommended, TB management practices. ,,, These deviations include under-utilization of sputum smear microscopy for diagnosis, generally associated with over-reliance on radiography; use of non-recommended drug regimens, with incorrect combinations of drugs and mistakes in both drug dosage and duration of treatment; and failure to supervise and assure adherence to treatment. The ISTC aims to address these widespread deficiencies by setting standards that all practitioners, irrespective of where they work, should aspire to follow while providing care to TB patients.
The ISTC is intended to be complementary to local and national TB control policies that are consistent with the WHO recommendations. The standards in the ISTC are not intended to replace local guidelines and were written to accommodate local differences in practice. They focus on the contribution that good clinical care of individual patients with or suspected of having TB makes to population-based TB control.
The basic principles of care for persons with or suspected of having, TB are the same worldwide: a diagnosis should be established promptly; standardized treatment regimens should be used with appropriate treatment support and supervision; response to treatment should be monitored; and essential public health responsibilities must be carried out. In keeping with these principles, the ISTC includes 17 standards that cover three broad areas: diagnosis, treatment and public health responsibilities. Of the 17 standards, nine standards are focused on diagnostic issues. , In this article, we present these diagnostic standards and describe their implications and relevance for laboratory professionals in India and worldwide.
All persons with otherwise unexplained productive cough lasting two-three weeks or more should be evaluated for tuberculosis.
All patients (adults, adolescents and children who are capable of producing sputum) suspected of having pulmonary tuberculosis should have at least two and preferably three, sputum specimens obtained for microscopic examination. When possible, at least one early morning specimen should be obtained.
For all patients (adults, adolescents and children) suspected of having extrapulmonary tuberculosis, appropriate specimens from the suspected sites of involvement should be obtained for microscopy and, where facilities and resources are available, for culture and histopathological examination.
All persons with chest radiographic findings suggestive of tuberculosis should have sputum specimens submitted for microbiological examination.
The diagnosis of sputum smear-negative pulmonary tuberculosis should be based on the following criteria: at least three negative sputum smears (including at least one early morning specimen); chest radiography findings consistent with tuberculosis; and lack of response to a trial of broad-spectrum antimicrobial agents. (Note: Because the fluoroquinolones are active against M. tuberculosis complex and, thus, may cause transient improvement in persons with tuberculosis, they should be avoided). For such patients, if facilities for culture are available, sputum cultures should be obtained. In persons with known or suspected human immunodeficiency virus (HIV) infection, the diagnostic evaluation should be expedited.
The diagnosis of intrathoracic (i.e, pulmonary, pleural and mediastinal or hilar lymph node) tuberculosis in symptomatic children with negative sputum smears should be based on the finding of chest radiographic abnormalities consistent with tuberculosis and either a history of exposure to an infectious case or evidence of tuberculosis infection (positive tuberculin skin test or interferon gamma release assay). For such patients, if facilities for culture are available, sputum specimens should be obtained (by expectoration, gastric washings or induced sputum) for culture.
All patients should be monitored for response to therapy, best judged in patients with pulmonary tuberculosis by follow-up sputum microscopy (two specimens) at least at the time of completion of the initial phase of treatment (two months), at five months and at the end of treatment. Patients who have positive smears during the fifth month of treatment should be considered as treatment failures and have therapy modified appropriately. In patients with extrapulmonary tuberculosis and in children, the response to treatment is best assessed clinically. Follow-up radiographic examinations are usually unnecessary and may be misleading.
In areas with a high prevalence of HIV infection in the general population and where TB and HIV infection are likely to co-exist, HIV counseling and testing is indicated for all tuberculosis patients as part of their routine management. In areas with lower prevalence rates of HIV, HIV counseling and testing is indicated for TB patients with symptoms and/or signs of HIV-related conditions and in TB patients having a history suggestive of high risk of HIV exposure.
An assessment of the likelihood of drug resistance, based on history of prior treatment, exposure to a possible source case having drug-resistant organisms and the community prevalence of drug resistance, should be obtained for all patients. Patients who fail treatment and chronic cases should always be assessed for possible drug resistance. For patients in whom drug resistance is considered to be likely, culture and drug susceptibility testing for isoniazid, rifampicin and ethambutol should be performed promptly.
The rationale and evidence base for each of these standards can be found in the ISTC publications. , Laboratory professionals play a critical role in ensuring that all of the above standards are actually met by providing high quality laboratory services for smear microscopy, culture and drug susceptibility testing [DST]) and other services such as testing for HIV infection. In the absence of such services, healthcare providers will not be able to make a rapid and accurate diagnosis of TB, HIV and drug resistance. In fact, if the ISTC is widely followed, it can be expected that there will be a greater need and demand for quality assured laboratory services and this will have obvious implications for all laboratories in terms of work load, requirement for resources and trained personnel and organization of external quality assurance (EQA) systems.
The ISTC re-emphasizes the importance of smear microscopy for TB diagnosis and treatment monitoring. Therefore, laboratories in India are obliged to provide high quality smear microscopy services to their customers, patients and providers alike. Because it is an old and laborious test, laboratories often ignore important published quality recommendations, ,, leading to inaccurate results. Before implementing culture, DST or novel tests, laboratories must be able to perform high quality smear microscopy. While the ISTC does not outline the specific techniques to be used for microscopy, there is evidence, cited in the ISTC, that the yield of microscopy can be increased by using fluorescent techniques and by concentrating sputum using a variety of methods. ,
Smear quality varies directly with accountability and any report produced in a laboratory that is not subject to external quality review must be considered suspect. Regular on-site visits by knowledgeable supervisors to assess accuracy and reliability of the results, infection control measures, condition of equipment, availability, expiry and purity of reagents and the direct observation of preparation, staining and examination of smears is essential. Random blinded rechecking of a sufficient number of slides provides internal accountability, but often "rechecked" results agree identically with screened slide results, indicating a breakdown in blinding. For this reason, EQA by panel testing is mandatory to maintain proficiency. Individual private laboratories can create a network for panel testing. The RNTCP has produced useful EQA guidelines that need to be widely used in the private sector. 
Lastly, high quality laboratory services are not uniformly available in India. Culture and DST are available only in tertiary care hospitals and reference laboratories. This lack of widespread laboratory support, unfortunately, will make it difficult for Indian healthcare providers to adhere to the ISTC. Thus, one important implication of the ISTC is the need for greater resources to establish a widespread network of laboratory services in India and to develop an appropriate referral mechanisms for prompt and safe transportation of specimens to referral laboratories, where clinical situations demand. Development of such a network should involve both governmental and private healthcare sectors. Such public-private partnerships are ongoing and further work is needed to ensure that such partnerships adopt and use the ISTC to improve laboratory capability. In fact, the full engagement of all care providers through various forms of public-private and public-public partnerships is an important component of both WHO's expanded strategy for tuberculosis control  and the Global Plan to Stop TB, 2006-2015.  Thus, associations such as the Indian Association of Medical Microbiologists (IAMM) should work together with the RNTCP and the private medical sector to come up with innovative approaches for providing adequate and accessible laboratory services in underserved areas.
| ~ Acknowledgements|| |
The ISTC report can be freely downloaded from several websites, including Stop TB: http://www.stoptb.org/resource_center/assets/documents/istc_report.pdf and WHO: http://www.who.int/tb/publications/2006/istc/en/index.html. The abbreviated publication can be downloaded freely from the Lancet website: http://www.thelancet.com/journals/laninf
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