Table 1.

Diagnostic criteria of NTM-LD.

Clinical criteria
1.Pulmonary symptoms, nodular or cavitary opacities on chest radiograph, or an HRCT scan that shows multifocal bronchiectasis with multiple small nodules. and 2.Appropriate exclusion of other diagnoses.
Microbiologic criteria
1.Positive culture results from at least two separate expectorated sputum samples. (If the results from the initial sputum samples are nondiagnostic, consider repeat sputum acid-fast bacilli smears and cultures.) or 2.Positive culture results from at least one bronchial wash or lavage. or 3.Transbronchial or other lung biopsy with mycobacterial histopathologic features (granulomatous inflammation or AFB) and positive culture for NTM or biopsy showing mycobacterial histopathologic features (granulomatous inflammation or AFB) and one or more sputum or bronchial washings that are culture-positive for NTM. 4.Expert consultation should be obtained when NTM are recovered that are either infrequently encountered or that usually represent environmental contamination. 5.Patients who are suspected of having NTM lung disease but who do not meet the diagnostic criteria should be followed until the diagnosis is firmly established or excluded. 6.Making the diagnosis of NTM lung disease does not, per se, necessitate the institution of therapy, which is a decision based on potential risks and benefits of therapy for individual patients.

AFB: acid-fast bacillus, HRCT: high-resolution computed tomography, NTM: nontuberculous mycobacteria.