Study objectives: To stratify COPD patients presenting with an acute exacerbation on the basis of sputum color and to relate this to the isolation and viable numbers of bacteria recovered on culture.

The problem with COPD is you have obstruction ... to look for in a flare-up is: Is their mucus getting worse? Is there more of it? Is it changing color? Is it going from its usual pale white ...

Patients presenting to their primary-care physicians with acute exacerbations associated with sputum production and underlying diagnoses of COPD were ... to a standard color chart.