The diagnostic yield and characteristics of bronchoalveolar lavage in suspected nontuberculous mycobacterial pulmonary disease.

Background: Bronchoalveolar lavage (BAL) has widely been used to manage respiratory diseases including respiratory infections. The aim of this study was to evaluate the diagnostic yield of BAL for detecting nontuberculous Mycobacterium (NTM).

Methods: We retrospectively reviewed the records of 54 patients who underwent bronchoscopy due to suspected NTM pulmonary disease. Positive culture results of respiratory specimens were defined as NTM pulmonary disease. For BAL, two or three aliquots of 50 mL (total 100 or 150 mL) of sterile normal saline were instilled through bronchoscope.

Results: NTM was detected in 31 of 54 (57.4%) patients. The detection rates were not different between the patients who underwent bronchoscopy with BAL (24 of 39, 61.5%) and those without (7 of 15, 46.7%) (P = 0.437). BAL fluid was mostly neutrophil dominant in both positive and negative NTM culture groups. In the subgroup analysis of 33 patients who underwent both the BAL and anti- glycopeptidolipid (GPL)-core immunoglobulin A (IgA) antibody measurements, 12 of 19 (63.2%) positive Mycobacterium avium complex (MAC) culture patients and 8 of 14 (57.1%) negative MAC culture patients were positive for anti-GPL-core IgA antibody (seropositive) (P = 0.991). There was no severe complication related to BAL.

Conclusions: The diagnostic yield of BAL with ≥100 mL sterile saline was not superior to that of bronchial wash or sputum aspiration in patients with suspected NTM pulmonary disease. Patients with seropositive but negative culture results for MAC suggest pseudonegative for pulmonary MAC disease.