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Background: Microbiological analysis of body fluids (BF) provides important information for diagnosis of infection. We evaluated the analytical performance of bacterial count by UF-4000 BF mode for ascitic, cerebrospinal, pleural, synovial and continuous ambulatory peritoneal dialysis fluids compared to classical microbiological procedure (direct Gram staining and culture)., Materials and Methods: For the 1,734 BF analyzed, distribution of UF-4000 bacterial count was analyzed according to the level of growth culture and results were compared using Mann-Whitney test. ROC curves analysis allowed to define the best cut-off value to predict or exclude positive culture for each type of BF., Results: UF-4000 bacterial counts were significantly lower in sterile than in infected BFs (p < 0.00001) and correlated with the level of growth on culture. The ROC curves of bacteria/μL and culture positivity yielded area under the curve >0.80 for each type of BF. Optimal cut-offs were chosen with excellent statistical parameters (sensitivity ranging from 0.70 to 0.86, specificity from 0.78 to 0.98, negative predictive value >0.95 and Youden index >0.55)., Conclusion: For BF, UF-4000 bacterial count correlate with culture results and is a discriminative method enhancing detection of microbiological etiology. It could be used as a screening method based on the cut-off values proposed in this study., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Background: Cytological analysis of body fluids (BF) provides important information for diagnosis in various medical conditions. We evaluated the analytical performance of the UF-4000 BF mode for ascitic, cerebrospinal, pleural, synovial and continuous ambulatory peritoneal dialysis fluids compared to light microscopy counting (LM)., Materials and Methods: 223 consecutive BF were analyzed by UF-4000 and results were compared using Pearson's correlation, Bland-Altman analysis, and contingence tests at relevant cut-off values. This study also included the evaluation of precision, linearity, and carryover., Results: For white and red blood cells (WBC, RBC) counts in all BF, correlation was excellent with Pearson's coefficients R 2  > 0,98. Bland-Altman analysis didn't reveal significant differences with limited bias for WBC ranging from -10 to -1 WBC/µL and bias ranging from -43 to -6/µL for RBC. At specific cut-off values for WBC, Se and Spe were 100% except for ascites (Spe = 98%) due to two false positive. Precision evaluated at three concentration levels was good for each parameter (WBC < 10%). Linearity was excellent for WBC (R 2  > 0,99) and carryover negligible (<0,004%)., Conclusion: UF-4000 BF mode is a good alternative to manual LM for BF cell counting. This automated method gives rapid and accurate results which is important for therapeutic decisions., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)