Table 5. Proposed diagnostic criteria for definite, probable, or possible pulmonary MAC and clinical classification as primary or secondary pulmonary MAC.

Definite MAC: specified findings from all 4 definite categories.

Probable MAC: specified findings from all 4 probable categories or 1–3 definite categories and the remainder from probable categorie(s)

Possible MAC: single positive sputum and documentation of treatment

1.Symptoms

Definite: pulmonary symptoms

Probable: pulmonary symptoms

2. Imaging

Definite: nodular or cavitary opacities on CXR or high-resolution CT that shows multifocal bronchiectasis with multiple small nodules

Probable: infiltrate, consolidation, or mass on CXR or CT scan

3. Microbiology

Definite:

(1) Positive culture from ≥2 separate expectorated sputum samples

Or

(2) Positive culture from ≥1 bronchial wash or lavage

Or

(3) Biopsy with mycobacterial histopathologic features and positive culture for NTM or biopsy showing mycobacterial histopathologic features and ≥1 sputum or bronchial washing that is culture positive

Probable: positive culture from 1 expectorated sputum sample

4. Exclusions

Definite: Appropriate exclusion of other possible causes of the clinical complex

Probable: Appropriate exclusion of other possible causes of the clinical complex

CLINICAL CLASSIFICATION

1. Primary: no smoking history and no known underlying pulmonary disease prior to the diagnosis of MAC pulmonary disease

2. Secondary: Smoking history or known underlying pulmonary disease prior to the diagnosis of MAC pulmonary disease (e.g. COPD, cystic fibrosis)