Fig. 1From: Circulating serotonin levels in COPD patients: a pilot studyBlood levels of serotonin in healthy subjects (n = 43) and in the totality of COPD patients (n = 43). The central horizontal line on each box represents the median, the ends of the boxes are 25 and 75 percentiles and the error bars 5 and 95%. P-values derived from Student’s t-testBack to article page