Anergy Testing for Tuberculosis

Tuberculosis (TB) is the second leading cause of death WORLDWIDE from a single infectious pathogen. Despite the fact that the majority of TB cases are in developing countries, this disease is also a problem in industrialized nations, such as the United States. Mycobacterium tuberculosis infects approximately 15 million people in this country, although it causes disease in many fewer. Even though this number is low compared to other countries, effective screening and treatment of latent infection is necessary to prevent new cases from emerging. After a healthy person is infected with M. tuberculosis, they have about a 10% lifetime risk for developing active TB. The highest risk for healthy patients occurs in the first 2 years after infection. The risk for conversion to active TB is increased among groups, such as children under the age of 2 and patients with comorbid conditions resulting in immunosuppression. The highest risk is associated with patients that have human immunodeficiency virus (HIV) infection. This risk is about 100 times higher than the normal population. In addition to the increased risk of active TB in HIV, TB may also have a detrimental effect on HIV. Due to the severity of active TB and the availability of medications to prevent it, effective testing for TB infection is necessary in high risk patients.