American Journal of Respiratory Critical Care Medicine 2007; 175:367–416

The minimum evaluation of a patient suspected of nontuberculous mycobacterial (NTM) lung disease should include the following: (1) chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan; (2) three or more sputum specimens for acid-fast bacilli (AFB) analysis; and (3) exclusion of other disorders, such as tuberculosis (TB). Clinical, radiographic, and microbiologic criteria are equally important and all must be met to make a diagnosis of NTM lung disease.