Correct diagnosis of TB is made on the basis of
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Positive sputum test
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Chest X-ray
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Tuberculin skin test
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All of the above
The Mantoux tuberculin skin test (TST) or the TB blood test can be used to test for M. tuberculosis infection. The Mantoux tuberculin skin test is performed by injecting a small amount of fluid called tuberculin into the skin in the lower part of the arm. The test is read within 48 to 72 hours by a trained health care worker, who looks for a reaction (induration) on the arm. A posterior-anterior chest radiograph is used to detect chest abnormalities in TB. Lesions may appear anywhere in the lungs and may differ in size, shape, density, and cavitation. The presence of acid-fast-bacilli (AFB) on a sputum smear or other specimen often indicates TB disease. A positive culture for M. tuberculosis confirms the diagnosis of TB disease.