The presence of Mycobacterium tuberculosis infection can be detected by a tuberculosis test approximately 3-6 weeks after the patient has contracted tuberculosis. A positive Mycobacterium tuberculosis test usually indicates infection with Mycobacterium tuberculosis. In healthy, immunocompetent people, if infected with Mycobacterium tuberculosis, the immune system will destroy most of the Mycobacterium tuberculosis, leaving only a small percentage dormant, which can remain latent in the body for a long time and become infected with Mycobacterium tuberculosis. For people with low immune function, the immune state of the body cannot destroy Mycobacterium tuberculosis, and Mycobacterium tuberculosis will multiply in the body, leading to inflammatory reactions in many organs and disease. Therefore, whether the disease develops after infection with Mycobacterium tuberculosis is related to the immunity of the body and the number and virulence of the infected Mycobacterium.