To be clear, not all TB patients are infectious. Tuberculosis is only highly contagious during the active phase, while patients with old tuberculosis are generally not contagious, but only in rare cases when immunity declines, resulting in old lesions becoming active again, which may be contagious to some extent. If you are worried that infection has occurred, you can observe yourself to see if there are uncomfortable symptoms such as coughing, coughing up sputum, weakness and low fever. Take care to wear a mask and isolate yourself from people around you, then go to the hospital. Perform an X-ray or CT examination to observe whether lung lesions are found, followed by a sputum examination to check for the presence of Mycobacterium tuberculosis in it. In addition to performing a systematic and comprehensive examination on your own, you can also ask the TB patient to undergo sputum smear and sputum culture together to clarify the presence or absence of infectiousness. If the patient is sputum positive, there is a risk of infection because Mycobacterium tuberculosis can be transmitted by droplets from a TB patient, so there is a risk of infection from kissing. If the test is negative, it usually means that the patient has old tuberculosis and is not usually infected with tuberculosis by kissing. If the test is negative and the patient is diagnosed with tuberculosis infection, he or she needs to cooperate with the doctor for a systematic and full course of treatment, including isoniazid, rifampin, pyrazinamide, ethambutol, etc. Be careful to wear a mask during treatment to avoid transmission to others.