This smear (usually of sputum) is used to support the diagnosis of tuberculosis (TB). The diagnosis of TB cannot be made with positive results of an AFB smear by itself. TB cultures are required. AFB smears are also used to monitor treatment of TB. The test is indicated in any patient with a persistent productive cough, night sweats, anorexia, weight loss, fever, hemoptysis, or abnormal chest x-ray. This smear should especially be considered in high-risk patients, such as those who are immunocompromised, are alcoholic, or have had a recent exposure to TB.