[The diagnosis of pulmonary tuberculosis].

Abstract

Mycobacterium tuberculosis (M. tuberculosis) infects all organs in the body; however, lung infection is the primary lesion. The total number of infections is decreasing, but the percentage of infections in older people is rising. Because this disease is due to infection with M. tuberculosis, the diagnosis requires the presence of M. tuberculosis. Chest X-ray and CT are very powerful tools to suggest the presence of M. tuberculosis infection. Pathological examination of the tissues also shows the typical findings of M. tuberculosis infection; however, the presence of the bacterium was not proven in certain cases of M. tuberculosis infection, and especially in cases of latent infection. Recently, the whole-blood interferon--gamma test (QuantiFERON-TB, QFT) became more popular than the tuberculin skin test. It is reported that the specificity and sensitivity of QFT are similar to or better than the tuberculin skin test. However, it should be noted that QFT positive does not automatically lead to a diagnosis of active M. tuberculosis infection and that QFT is one of the supplementary tests in the diagnosis of M. tuberculosis infection. Currently, massive infection with M. tuberculosis is increasing. The precise responsible linkage in massive infection with M. tuberculosis needs DNA polymorphism analysis using variable numbers of tandem repeats (VNTR) or restricted fragment length polymorphism (RFLP).