A negative Mycobacterium tuberculosis DNA means that the patient was not found to be infected with Mycobacterium tuberculosis. However, Mycobacterium tuberculosis DNA negative does not necessarily mean that there is no Mycobacterium tuberculosis in the body. If there is a trace amount of Mycobacterium tuberculosis infection in the body, the content of Mycobacterium tuberculosis in the patient’s body is relatively low and cannot reach the lower limit of detection of the instrument. Or the replication of Mycobacterium tuberculosis genes in the early stage of infection has not reached a certain amount, so it cannot be detected, which is the window period in medical science nowadays. Therefore, clinical symptoms and other testing indicators should be analyzed, and if necessary, Mycobacterium tuberculosis needs to be reviewed to determine whether the patient is infected with Mycobacterium tuberculosis, and if the patient is diagnosed with Mycobacterium tuberculosis infection, anti-tuberculosis treatment is required.