Thanks to the availability of two new blood tests called T-SPOT.TB and QuantiFERON-TB Gold, physicians around the world can better detect latent tuberculosis (TB) infection. The tests, which reduce the number of false positive and negative results inherent to the old tuberculin skin test, are just two examples of clinical advances in TB control that could potentially eliminate the disease during the 21st century.
This update on TB diagnosis and treatment appears in the first issue for October 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Luca Richeldi, M.D., Ph.D., of the Department of Oncology, Hematology and Respiratory Disease at the University Policlinco of Modena in Modena, Italy, highlighted the significant operational advantages of the new blood tests over the skin test: The new tests require no return visit, provide results the next day and are significantly more accurate than the tuberculin skin test.
The fact that the blood tests do not usually indicate disease in healthy people is especially important in populations that have had the bacillus Calmette-Guerin (BCG) vaccine. BCG is the most widely used vaccine in the world; to date, more than three billion people have received it.
"Targeted tuberculin testing for latent TB infection is a key component of TB control," said Dr. Richeldi. "It is based on identification and treatment of persons infected by Mycobacterium tuberculosis who are at high risk for progression to active disease. This strategy is powerful because preventive treatment of latently infected people diminishes the risk of subsequent development of active TB by about 90 percent."
The T-SPOT.TB and QuantiFERON-TB Gold, tests detect interferon gamma released in T cells in response to M. tuberculosis- specific antigens. (T cells, a type of white blood cell, produce a number of substances that regulate the bo
Contact: Suzy Martin
American Thoracic Society