IntroductionBody fluids, including pleural, peritoneal (ascites), pericardial, and cerebrospinal effusions, consist of testing parameters which provide diagnostic values by examining the biochemical analytes and cellular components, such as infiltrating benign and malignancy cells [1,2]. The evaluation of the cellular compositions in these specimens is performed in either the hematology laboratory or the cytology laboratory or both, on the samples which were concomitantly collected but independently processed. The hematology expertise of medical technologists provides primarily reports based on absolute and differential hematological cell counts in the paired specimen of body fluid and peripheral blood, and screens for any suspicious malignant cells of other tumor types along with hematological lineage of differential precursors. Meanwhile, the cytology expertise of pathologists centrally checks for the presence of malignancy at a diagnostic-level rather than at a screening-level, yielding various sensitivities as reported; for example, an average of around 70% in detecting malignant cells in pleural fluid [3] and 40-65% in peritoneal fluid [4]. The diagnostic yields for malignancy by cytology might vary due to personnel skills and likewise depend on tumor and effusion types Abstract Objective: An increasing burden is loaded on clinical laboratories for daily testing of body fluids, including pleural fluid, peritoneal fluid (ascites), pericardial fluid, and cerebrospinal fluid. The request for detection of cellular components in the body fluid samples is usually delivered simultaneously to the hospital's hematology laboratory and cytology laboratory. The medical technologists of hematology laboratory provide the screening result for suspicious malignant cells; meanwhile, the pathologists of cytology laboratory provide the presence of cancer cells at a diagnostic level. However, unfortunately, neither of these results reaches 100% sensitivity or specificity. To assess the clinical practice values, the present study performed a comparison of the hematology and cytology laboratories on the detection of malignancy in body fluids. Methods:The body fluid specimens were collected either in the absence or in the presence of an anticoagulant agent, such as heparin. The finding of body fluid malignancy was remarked along with the differential count of blood cells in the report. Cytology laboratory, the body fluid specimens were subjected to cytospin centrifugation, followed by Papanicolaou stain, and then the morphological results were graded as negative, atypical, suspicious or positive for malignancy. The agreement of body fluid malignancy between the hematology laboratory and cytology laboratory was assessed by Kappa statistics and the differences between the groups were evaluated by chi-square test.Results: A total of 248 body fluid samples, including 191 (77.0%) pleural fluids, 50 (20.1%) ascites, 4 (1.6%) pericardial fluids, and 3 (1.2%) cerebrospinal fluids were retrospectively surveyed in the National Cheng Kung Un...