Which diagnostic test is identified as the major screening tool for pulmonary tuberculosis?

• A. Chest X-ray
• B. Sputum examination
• C. Sputum culture
• D. Blood test

Answer: (B)

The main idea is that sputum examination directly looks for the presence of Mycobacterium tuberculosis in the airways, making it the most practical screening tool for pulmonary TB. Sputum smear microscopy is quick, inexpensive, and widely available, so it can identify infectious individuals promptly and guide immediate isolation and treatment decisions. While chest X-ray can suggest TB and is useful for supporting diagnosis, it isn’t specific—many other conditions can mimic TB on imaging. Sputum culture is more sensitive and confirms TB, but it takes longer and requires more resources, so it’s not used as the first-line screening test. Blood tests aren’t used to screen for pulmonary TB.