Association of sputum colour score with (A) total cell counts; (B) neutrophil proportion; (C) neutrophil number and (D) CXCL-8 concentration. Association of sputum colour score with (A) total cell counts; (B) neutrophil proportion; (C) neutrophil number and (D) CXCL-8 concentration. Horizontal bars represent median values; p<0.001 (Kruskal-Wallis and Dunn’s multiple comparison test); p<0.05 versus *sputum colour score 1 and #sputum colour score 2. Kavita Pabreja et al. BMJ Open Resp Res 2017;4:e000236 ©2017 by British Thoracic Society