ObjectiveTo investigate the clinical value of DNA ploidy analysis system in the diagnosis of benignancy or malignancy with bronchial brushing or bronchoalveolar lavage fluid. MethodsWe studied 96 bronchial brush tablets or bronchoalveolar lavage fluid specimens confirmed pathologically between June 2012 and June 2013, in which there were 49 cases of benignancy and 47 malignancies. Bronchial brush pieces were acquired by clinicians when they performed bronchoscopy for the patients. Each bronchoalveolar lavage fluid specimen was made into two slides, of which one was stained by HE method for cytology analysis, and the other was stained with Feulgen method for DNA ploidy analysis through automatic imaging cytometer. ResultsThe specificity, sensitivity and accuracy of the routine cytological investigation were respectively 85.7%, 78.7% and 77.1%, while the three indexes for DNA ploidy analysis were 100.0%, 91.5% and 95.8%, respectively. ConclusionDNA ploidy analysis can improve the bronchial brushing or bronchoalveolar lavage fluid positive rate, and compared with cytological investigation, it is more specific and more sensitive with a high clinical value.