TB of the lungs can be revealed through chest x-ray and sputum examination

TB of the lungs is usually detected in the chest radiograph (x-ray). The imaging procedure is safe. Pregnant women should inform about their condition before the chest x-ray is taken.

Patient’s sputum (phlegm coughed up) samples are also examined. Microscopic examination of sputum is done to find out if there are bacteria in the sputum and if the patient is infectious. Culturing the sputum specimen is necessary to determine whether it contains bacteria that cause TB disease. If necessary, a rapid DNA-based diagnostic test for TB is performed.

A small child swallows sputum and cannot produce samples as adults. If TB of the lungs is suspected, gastric aspiration (a small tube is inserted through the patient’s nose and passed into the stomach to get a sample of sputum that was coughed into the throat and then swallowed) can be used to get a sputum sample for testing. It is performed in the hospital.

Sometimes it is necessary to perform a bronchoscopy or computed tomography (CT) of the lungs.

Various imaging techniques are used when examining TB in other sites than lungs. In addition, a sample of the tissue or pus from the body site where the disease is located is taken and examined.