Diagnostic criteria of bronchiolitis obliterans syndrome following haematopoietic stem cell transplantation

  • FEV1/FVC ≤0.7

  • FEV1≤75% of predicted with at least 10% decline from baseline, no significant post-bronchodilator response

  • Additional evidence of small-airway disease (at least 1 out of 3)

    • Evidence of air trapping, small-airway thickening or bronchiectasis on high-resolution computed tomography of chest (with inspiratory and expiratory cuts)

    • Residual volume 120%, or elevated residual volume/total lung capacity

    • Pathologic confirmation of constrictive bronchiolitis

  • Absence of infection in the respiratory tract

    • By appropriate clinical, radiologic, microbiologic studies (sinus aspiration, upper respiratory tract, viral screen, sputum culture or bronchoalveolar lavage)

FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity.