Abstract: Objective　To evaluate the clinical application value of routine cytomorphology examination in 860 bronchoalveolar lavage fluid samples collected from January 2005 to December 2010 in Changhai Hospital by retrospective analysis. Methods　The 510 mL bronchoalveolar lavage fluid was collected in 10 mL plastic centrifuge tube and was centrifuged (500 g，5 min). The sediment was then loaded on microscopic slides, and ordinarily 6 smears were produced， including 2 thick slides without tails， 2 thick slides with tails and 2 thin slides with tails. WrightGiemsa was performed, and the monocytes/macrophages， lymphocytes， neutrophils， eosinophils， et al, cytomorphology and abnormal constituents were further counted and differentiated by experienced technicians under light microscopy. Periodic acidSchiff (PAS) stain and hemosiderin staining were also performed if necessary. Results　Neutrophil ratio >2% or 20% accounted for 88.8% (764 cases) or 47.2 % (406 cases) of the total 860 patients， respectively. Lymphocyte ratio >12% or 20% accounted for 27.2% (234 cases) or 15.7% (135 cases)， respectively. Eosinophil ratio>1% or 10% accounted for 7.4% (64 cases) or 3.2% (32 cases). A total of 117 cases accounted for 13.6% were found to have abnormal constituents， including cancer cells in 16 cases， heterogeneous nuclear or suspected cancer cells in 43 cases， fungus in 14 cases， Pneumocystis carinii in 3 cases and phagocytes in 2 cases. PAS stain positive had 33 cases, and hemosiderin staining positive had 6 cases. There were only 46 samples in which no abnormality was identified， accounting for 5.3% of total cases. Conclusions　High detection rates of abnormality in bronchoalveolar lavage fluid are identified, the high detection rates can provid helpful clinical reference for the diagnosis， treatment and prognosis of various diseases.

Key words: Bronchoalveolar lavage fluid, Cytomorphology, Abnormality detection rate