Table 1.

Review eligibility criteria

Inclusion criteria	Exclusion criteria
Participants
Participants diagnosed with acute exacerbation of COPD	Stable COPD
Index test
Sputum colour macroscopically assessed by professional healthcare worker or patient reported
Reference standard
Quantitative culture for potentially pathogenic bacteria on an adequate sputum sample (according to the Murray-Washington or Bartlett criteria)
Outcome
Data required to populate 2 X 2 table: sensitivity and specificity or true positives, false positives, false negatives and true negatives
Study design
Prospective studies	Case reports
Retrospective studies	Case series
Cross-sectional studies	Ecological studies
	Diagnostic case control studies with healthy controls