If your doctor finds abnormal shadows in your lungs, he or she will give you a sputum examination. Sputum examination is the most accurate way to diagnose tuberculosis and find the source of infection. In addition, the patient’s doctor will ask you to check sputum regularly during the treatment to evaluate and assess the effect of treatment. A patient with positive sputum is cured of tuberculosis after three consecutive negative sputum tests at the end of the course of treatment.