Introduction: Understanding risk factors for non-tuberculous mycobacterial pulmonary disease (NTM-PD) is challenging and current testing in high-risk groups is potentially suboptimal.

Aims: To identify risk factors that should prompt testing for NTM-PD.

Methods: 12 European NTM-PD experts reviewed NTM-PD testing parameters through a modified DELPHI process over 3 rounds of voting (Likert scale 1?9) and discussion. Voting results are presented as mean ± SD.

Results: Patients with thoracic imaging suggestive of NTM-PD (9.0±0.0), recurrent respiratory infections (range 6.3±1.6 to 8.3±0.8), or haemoptysis (range 6.3±2.3 to 8.8±0.3) and patients presenting with >3 symptoms suggestive of NTM (range 6.9±1.5 to 8.8±0.6) were highly recommended for testing irrespective of the underlying disease. Bronchiectasis, cystic fibrosis (CF), and previous tuberculosis or NTM-PD should prompt testing, particularly in patients with recurrent respiratory infections (range 7.5±1.4 to 8.3±1.2). Inhaled corticosteroid use should prompt testing in patients with bronchiectasis (7.8±2.3) or CF (7.8±2.3), as should the prescribing of long-term macrolide therapy in patients with underlying respiratory conditions (range 7.1±2.5 to 8.1±2.3). Experts suggested that asymptomatic patients should only be tested for NTM-PD based on immunosuppressant use and underlying lung disease or a prior history of NTM-PD (8.9±0.3) .

Conclusion: The findings from this DELPHI process may help clinicians target patients most at-risk of developing NTM-PD for testing and enable timely diagnosis and patient management.