Luncheon Workshop 2 Performance Evaluation of the Body Fluid Module on the Sysmex XN-2000 Young-Uk Cho Department of Laboratory Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea Body fluid analysis • Cell count & differential – CSF • Meningitis, encephalitis, multiple sclerosis, cerebral hemorrhage – Ascitic fluid • SBP, CAPD peritonitis – Pleural fluid • Pulmonary tuberculosis, empyema – All types • Metastatic tumors Body fluid analysis “Gold standard” for the determination of WBC and RBC in fluids Labor-intensive High inaccuracy High imprecision High inter-observer variability Automatic hematology analyzer equipped with an body fluid (BF) mode Sysmex XN series - BF module Fluorescent flow cytometry High-fluorescent cells No pre-treatment Large amount of nucleic Reduce time, labor and manual counts acid Our experience • A total of 405 samples – – – – 176 ascitic fluid 131 pleural fluid 77 CSF 21 other type fluid • 8 pericardial fluid • 9 bronchoalveolar lavage fluid • 3 CAPD fluid • 1 joint fluid - methods • 125 malignant samples – 115 carcinomas – 9 leukemia or lymphoma – 1 malignant melanoma Our experience - methods • Precision – Serially diluted BF XN-check samples • Assessed 10 times on the analyzer in the QC mode – Lower limit of quantitation • The point where the CV > 20% • Between-run precision – Two levels of BF XN-check over 18 days Our experience - methods • Accuracy – Comparison with manual microscopic method • WBC, RBC, PMN, MN – Regression analysis • Only on samples with RBC counts ≥ 1,000/μL • Linearity – Serial dilution of high WBC or RBC counts Our experience - results Precision curve for total WBC count assessed using the Sysmex XN on BF module. The lower limit of quantiation was 5.8/μL. The between-run precision was always < 6.1% for all parameters. Our experience - results Cell count agreement between Sysmex XN analyzer and manual microscopic examination 100 MN cell Sysmex XN (%) 100 80 60 40 20 80 60 40 20 0 0 CSF 0 20 40 60 80 PMN cell cytospin (%) 100 20 40 60 80 MN cell cytospin (%) 0 20 40 60 80 MN cell cytospin (%) 100 100 MN cell Sysmex XN (%) 100 80 60 40 20 80 60 40 20 0 0 Others 0 0 20 40 60 80 PMN cell cytospin (%) 100 100 Correlation of cell counts from body fluids between automated and manual counting methods. Samples containing malignant cells were excluded from the analyses 100 Sensitivity 80 60 40 20 0 0 20 40 60 80 100-Specificity 100 The median number of HF-BF cells was significantly higher in the samples containing malignant cells than in those without malignant cells [17.8/100 WBC (range: 0.5 – 411) and 4.15/100 WBC (range: 0 – 168.8), respectively, P < 0.0001]. The ROC plots revealed that the number of HF-BF cells had an area under the ROC curve of 0.791 (95% confidence interval = 0.748 – 0.829) for identification of samples containing malignant cells, demonstrating a sensitivity of 87.2% and a specificity of 60.4% at the cutoff point of 6.9 HF-BF cells/100 WBC. 123.5/100 WBC 58.1/100 WBC 102.1/100 WBC Characteristics of cases with exceptionally low numbers of HF-BF cells despite the presence of malignant cells P = 0.002 Correct positive (N=109) False negative (N=16) P = 0.799 Correct positive (N=109) False negative (N=16) Conclusion • The BF mode on the Sysmex XN automatic hematology analyzer is a rapid, reliable, and accurate method for counting blood cells and WBC differential in body fluid samples with a few drawbacks. • It is feasible to use automated method for the diagnostic workup of non-CSF fluids suspected of benign condition. • However, in cases where the high-fluorescent cell concentration is greater than the given threshold, additional evaluation by manual microscopy should be automatically triggered. Thank you for your attention!
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