RESULTS: The qualified sputum samples were obtained from 153 subjects with a success rate of 82.7% (153/185). Mean age of subjects was 43 year old. The mean, median (95%CI) total cell counts was 2.1×106/g, 2.0×106/g (0.7-4.5×106/g), The mean, median (95%CI) differential cell counts were as follows: neutrophil 38.6%, 36.4% (8.9%-73.8%); macrophage 59.5%, 61.0% (24.7%-90.0%); eosinophil 0.6%, 0.3% (0.0%-2.0%); lymphocyte 1.2%, 1.0% (0.0%-4.5%). There was positive correlation between the percentage of neutrophil and eosinophil and age (r=0.658, r=0.404; P<0.001), while a negative correlation was found between percentage of macrophage and age (r =-0.660, P<0.001). The percentage of neutrophil, macrophage and eosinophil were significantly different among different age groups. The total cell counts and sputum cell counts were comparable between male and female.