Reference	Objective	Design	Evidence
Aaron et al. [473]	To determine if PSI of biofilms of cystic fibrosis patients yields additional P. aeruginosa isolates cf sputum culture	PCS	3A? small numbers
Allegra et al. [458]	Colorimetric and detailed microbiological assessment of sputum in a large sample of COPD patients of varying clinical severity	PCS	3A+
Murphy et al. [166]	To establish causal link viz AECOPD and Moraxella in a longitudinal cohort with molecular microbiological testing of sputum and serology	PCS	3A? there have been previous studies that found little evidence of moraxella involvement
Murphy et al. [469]	Longitudinal molecular analysis of H. influenzae isolates from sputum	PCS	3A+
Papi et al. [167]	Prospective study of diagnostic yield from sputa from patients during and after exacerbations of COPD	PCS	3A+
Sethi et al. [472]	Longitudinal study of COPD patients including detailed analysis of serological responses during exacerbations	PCS	3A+
Wilkinson et al. [470]	Correlation of sputum bacterial load with clinical features and severity of longitudinal series of COPD patients	PCS	3A+
Sethi et al. [471]	Detailed longitudinal study of quantitative sputum counts comparing stable and exacerbation periods	PCS	3A+
Murphy et al. [85]	Acquisition of a new stain of P. aeruginosa is associated with exacerbations of COPD	PCS	3A+