Proportion of the positive sputum culture of sputum specimens following Bartlett criteria ≥ +1, ≥ +2, ≥ +3 are 32.7%; 31.03%; 32.86% respectively. Proportion of the positive sputum culture of sputum specimens following criteria of squamous epithelial cells < 10 and criteria of squamous epithelial cells < 10 and leukocytes > 25 are 30.62%; 28.48% respectively.