Performance evaluation of UF-4000 body fluid mode for automated body fluid cell counting

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 R² > 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 (R² > 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.