Tuberculosis Diagnostic Methods Research Articles

Tuberculosis Epidemiology, Diagnosis and Infection Control Recommendations for Dental Settings: An Update on the Centers for Disease Control and Prevention Guidelines

Although rates of tuberculosis (TB) in the United States have decreased in recent years, disparities in TB incidence still exist between U.S.-born and foreign-born people (people living in the United States but born outside it) and between white people and nonwhite people. In addition, the number of TB outbreaks among health care personnel and patients has decreased since the implementation of the 1994 Centers for Disease Control and Prevention (CDC) guidelines to prevent transmission of Mycobacterium tuberculosis. In this article, the authors provide updates on the epidemiology of TB, advances in TB diagnostic methods and TB infection control guidelines for dental settings. In 2008, 83 percent of all reported TB cases in the United States occurred in nonwhite people and 17 percent occurred in white people. Foreign-born people had a TB rate about 10 times higher than that of U.S.-born people. New blood assays for M. tuberculosis have been developed to diagnose TB infection and disease. Changes from the 1994 CDC guidelines incorporated into CDC's "Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005" include revised risk classifications, new TB diagnostic methods, decreased frequencies of tuberculin skin testing in various settings and changes in terminology. Although the principles of TB infection control have remained the same, the changing epidemiology of TB and the advent of new diagnostic methods for TB led to the development of the 2005 update to the 1994 guidelines. Dental health care personnel should be aware of the modifications that are pertinent to dental settings and incorporate them into their overall infection control programs.

New diagnostic methods for tuberculosis

During the last decade, laboratory tests for the detection of Mycobacterium tuberculosis (Mtb) have improved dramatically. Improvements in the ability to detect latent infection with Mtb, disease associated with Mtb, and strains resistant to commonly used antibiotics are reviewed. Advances in the detection of Mtb include light-emitting diode fluorescence microscopy, nucleic acid amplification of Mtb and drug-resistant strains, and more rapid liquid culture with adjunct drug susceptibility testing. In the detection of latent tuberculosis infection, interferon [gamma] release assays offer improved accuracy over the tuberculin skin test. The past 10 years have seen the most rapid growth in new diagnostics for Mtb in over a century. Although these tests offer improvements in the ability to detect Mtb, drug-resistant isolates, and those with latent tuberculosis infection, these improvements are counter-balanced by the need to deploy these tests in areas where Mtb burden is highest.

Diagnostic Methods for Tuberculosis

Tuberculosis (TB) is a major public health problem especially in the third world countries. In India, it is estimated that at present there may be approximately 10 million persons suffering from radiologically evident pulmonary TB of whom about 2.5 million would be sputum positive. The number of deaths due to tuberculosis is estimated to be approximately 5,000,000 every year. Definitive diagnosis of tuberculosis depends on smear examination and culture of appropriate biological fluids. Only up to 50% of pulmonary and 25% of extrapulmonary TB are diagnosed by smear examination. Traditional culture methods take around 6 weeks before the diagnosis can be established. Chemotherapy for tuberculosis is prolonged, expensive and not free from serious side effects. If the diagnosis of TB is delayed, it leads to increases morbidity and in some cases mortality (e.g. tuberculous meningitis). Often the clinicians have to start therapy empirically. There is a great need, therefore, for tests which are highly sensitive and specific as well as rapid.