Abstract: The judgment of tuberculosis (TB) activity is based on clinical manifestation, sputum bacteria, blood test, tuberculin skin test and imaging examination, and the judgment of communicable TB is based on quantity of discharged bacteria, lesion and symptom, size of discharge droplets, level of contact with the patients
and environmental factors. Isolating contagious patients as soon as possible, cutting off transmission routes and protecting susceptible population are the basic requirements in controlling TB.

Key words: Tuberculosis, Activity, Communicable, Judgment, Prevention and control