Background: We evaluated the reliability of cell count and WBC differential count for different sources of body fluid (BF) speciment and the clinical significance of high fluorescence cells (HF-BF)by the BF mode of XE-5000 hematology analyzer.Methods: RBC, WBC, differential count and HF-BF% of BF [112 benign and 18 malignant specimens.Also say, 57 serous cavity effusion, 24 cerebrospinal fluid (CSF),44 bronchoalveolar lavage fluid (BALF), and 5 other drainage] were measured and compared to the microscopy analysis, Wrights-Giensa and Hematioxylin-Eosin (HE).Results: The consistency for serous cavity effusion and CSF (ICC > 0.9518) was superior to that of BALF (ICC < 0.8986) was superior to that of BALF (ICC < 0.8986).The consistency of differential count for serous cavity effusion (MN% > 0.8413,PMN% > 0.8950, EOS% > 0.9048 and HF-BF% > 0.7715) Were superior to that for CSF and BALF (MN% < 0.7276, PMN% < 0.7525, EOS% < 0.8421 and HF-BF% < 0.1615).The poor precision (CV>20%) was obtained from 14 specimens with RBC≤490×106/L,including 8 CSF, 5 serous cavity effusion and 1 drainage.The median HF-BF% of benign BALF was 31.1% was higher than that of malignant specimens (23.7%).The area under ROC curve of HF-BF% for predicting large cells (A=0.803) was better than for predicting tumor cells (A=0.712), the sensitivity and specificity for predicting larege cells were 0.83% and 0.71%, respectively.Conclusions: WBC differential count for serous cavity effusion was better that that of CSF and BALF, and the HF-BF% for predicting the large cells superior to tumor cells by the BF mode of XE-5000 hematology analyzer.