Evaluation of high-fluorescence body fluid (HF-BF) parameter as a screening tool of malignancy in body fluids

Automated body fluid (BF) analysis is gradually replacing the traditional methods of cell counting in all BFs. This study was done to analyze the high-fluorescence (HF)-BF parameter generated on Sysmex XN-1000 and study its correlation with the presence of malignant cells in the body fluids. A correlation between manual and automated differential counts was also done.

A total of 1985 samples including 797 ascitic fluids (AF), 532 pleural fluids (PF), and 656 cerebrospinal fluids (CSF) were run on Sysmex XN-1000 in BF mode and cytopathology was available for 924 BFs including 389 AF, 379 PF, and 156 CSF. Both manual and automated methods were used for cell differential and cell morphology.

Of the 924 samples with corresponding cytopathology, malignancy was found in 59 samples. The HF-BF%/100 WBCs (24.8 ± 72.5) and HF-BF#/μL (329.86 ± 932.35) for malignant BF samples were found to be significantly higher than the nonmalignant samples (4.41 ± 8.1) and (19.57 ± 61.91), respectively. Receiver-operator-characteristic curve cutoffs for all BF for percentage and absolute HF-BF were 2.85%/100 WBCs and >12/μL. A good correlation was found between the manual and automated WBC differential counts in all fluids except CSF with total count < 5/μL.

BFs can be reliably analyzed on automated analyzers. HF-BF parameter is helpful in identifying malignant samples but cannot be totally relied upon. If HF-BF%/# are above the lab-generated cutoffs, microscopy should be done. A complete validation study on HF-BF parameter in BF mode is desired to set the standards for the analysis of serious effusions.