Which statements confirm active TB infection?

• A. The presence of symptoms, positive sputum culture, and chest X-ray
• B. A normal chest X-ray with no symptoms
• C. A negative sputum culture but positive TST
• D. A positive Mantoux test alone

Answer: (D)

Active TB diagnosis relies on microbiologic confirmation along with clinical and radiographic evidence. A positive Mantoux test indicates TB exposure but does not prove the disease is active; many people with a positive TST have latent TB or past exposure rather than active infection. A normal chest X-ray with no symptoms cannot indicate active TB, and a negative sputum culture with a positive TST suggests latent infection rather than active disease. The scenario that includes symptoms, a positive sputum culture, and chest X-ray findings characteristic of TB provides the necessary evidence that TB is active, because it combines clinical illness with microbiologic confirmation and imaging consistent with disease.