Abstract Introduction/Objective Although microscopic examination is the gold standard for body fluid malignant cytology, it has a higher turnaround time and inter observed variability. Screening of serous effusions for malignant cells using haematology methods of automated analysis provides a rapid and objective result to the clinicians for initiating necessary treatment. Automated haematology analysers are equipped with body fluid (BF) mode that can detect high fluorescence cells body fluid (HF-BF) cells, mononuclear and polymorphonuclear (PMN) cells using flowcytometry laser scatter principles. The high fluorescence parameters useful for identifying malignant cells in the effusions Methods/Case Report The study was performed between February 2023to Februart 2024 at AIG Hospitals, Hyderabad after obtaining approval from the medical ethics committee of thehospital. Body fluidswere collected in K2 EDTA vaccutainer. Simultaneous preparation of smears for microscopic examination and morphometry wasdone and the smears were stained using Romanowsky stain (Leishmann & Giemsa). Cytospin smears were prepared by cyto- centrifugation (Sakura cyto- tix). The slides were stained by Hematoxylin and eosin, May Grunwald Giemsa (MGG) and Papanicolaou (PAP) stains for morphological differentiation and detection of malignant cells. Cell blocks were prepared after through mixing of the fluid using direct sedimentation method and the slides were stained by haematoxylin and eosin stain. IHC was performed where ever necessary. Results (if a Case Study enter NA) A total of 258 fluid samples comprising of 223 ascitic and 35 pleural fluids. Medical statistical software version 20.2 was used for statistical analysisof the results. Considering fluid cell block analysis as the gold standard the patient population was divided into 2 groups, malignant (8 samples) and non- malignant cell group(250 samples). Cytological examination of cytospins smears has shown to have the highest specificity, PPV and NPV in the detection of malignant effusions. Conclusion Our study shows that cytology and histopathological examination of body fluids remains the gold standard for the detection of malignant cells. The HF-BF parameter acts as a rapid, useful tool to predict the presence of malignant cells in serous effusions and select samples for microscopic reviewing that would have otherwise gone undiagnosed. We believe that with defining cut off values for the HF-BF parameter may be used as an adjunct diagnostic tool.