The most important means of checking whether TB is contagious or not is the sputum tuberculosis smear test and sputum bacterial culture. If the sputum smear and sputum culture are positive, it means that the TB patient has excreted bacteria and is infectious. Personal protection, respiratory isolation, and active anti-tuberculosis treatment should be carried out until the disease is stabilized and the patient is free of TB bacteria before continuing to work and study. If the sputum smear and sputum culture are negative, it means that the patient’s contagiousness is relatively low, or there may be no contagiousness, so sputum examination is the most critical means of determining whether a tuberculosis patient is contagious.