Fig. 3From: Measurement of C-reactive protein, procalcitonin and neutrophil elastase in saliva of COPD patients and healthy controls: correlation to self-reported wellbeing parametersSalivary Procalcitonin (PCT) levels from healthy non-smokers, healthy smokers, stable COPD subjects. The horizontal bar represents the median; the box length represents the interquartile range. Outliers are identified by o (1.5 x the interquartile range) and * (3 x the interquartile range)Back to article page