Generally, it can be detected by skin test, i.e. tuberculin skin test, about 1~3 months after contact with a patient with cavitary tuberculosis, but the exact time of detecting whether the patient is infected with the disease is affected by factors such as individual’s physical condition and it is not a certainty that the patient will be infected with the disease after contact with a patient with cavitary tuberculosis. Cavitary TB, like other types of TB, is spread through droplet transmission and has an incubation period of about 1 to 2 months, but the incubation period and onset of the disease varies depending on the individual’s physical condition. Usually, a tuberculin skin test or CT examination can be performed 1~3 months after exposure to see if the exposed person is infected with Mycobacterium tuberculosis. It is not always possible to become infected with Mycobacterium tuberculosis after contact with a patient with cavitary TB. If the person with cavitary TB is a non-exploiter, or if the person with cavitary TB has anti-tuberculosis antibodies in his or her body, he or she may not be infected with TB. The tuberculin skin test is not the only criterion for determining whether or not a person is infected with C. difficile. In order to confirm the diagnosis of the disease, a combination of sputum cultures, sputum smears, imaging tests, clinical symptoms, and history of exposure is needed.