A comparison of the analysis of 3 types of body fluids using the XN-350 hematology analyzer versus light microscopy assessment

Analytical performance of the digital morphology analyzer Sysmex DI-60 for body fluid cell differential counts

BACKGROUND

Sysmex DI-60 (Sysmex, Kobe, Japan) is a digital morphology (DM) analyzer widely used in clinical laboratories and supports body fluid (BF) applications. We evaluated analytical performance of DI-60 compared with XN-350 (Sysmex) and manual counting for BF cell differential counts.

METHODS

A total of 213 BF samples were collected (47 cerebrospinal fluid [CSF], 80 pleural fluid, and 86 ascites samples). The analytical performance of DI-60 for BF cell differential counts was evaluated based on sensitivity, specificity, accuracy, and agreement. BF cell differential counts obtained by DI-60 were compared with those obtained by XN-350 and manual counting.

RESULTS

The overall sensitivity was high for neutrophils, lymphocytes, and macrophages (range, 83.1-99.4%). The overall specificity and overall accuracy were high for all cell types (range, 95.3-99.7% and 94.3-99.3%, respectively). The agreement between DI-60 pre-classification and verification was strong (κ = 0.89). The absolute mean differences between DI-60 verification and XN-350 ranged from 0.26 to 11.05, and differences between DI-60 verification and manual counting ranged from 0.01 to 4.76.

CONCLUSIONS

This is the first study to evaluate the performance of DI-60 compared with XN-350 and manual counting for BF cell differential counts. DI-60 showed reliable performance with CSF, pleural fluid, and ascites samples. For BF cell differential counts, DI-60 may be a better option than XN-350 and could be used for screening purposes in understaffed laboratories. To improve the hematology workflow for BF cell differential counting, the DM analyzer needs to be optimized by taking into account the laboratory situation and unmet needs, and the clinical laboratory needs to establish criteria for verification and manual slide review.

Automated and manual microscopic analyses for leukocyte differential counts in exudative pleural effusions: Real-world disagreement and clinical application

Differential leukocyte counts of pleural fluid are routinely recommended for the early diagnosis and management of exudative pleural effusions. Rapid automated cellular analysis agrees strongly with standard manual microscopic counts and has become a reality in many clinical laboratories. However, discordant results sometimes observed between automated and manual analyses raise concern about using automated analysis to aid prompt differential diagnosis. This study aimed to evaluate the real-world disagreement between automated and manual leukocyte analyses in exudative pleural effusions and to investigate whether the discordant results occur in specific cellular ranges or randomly. We conducted a retrospective study of patients who were diagnosed with parapneumonic pleural effusions (PPE), tuberculous pleural effusions (TPE), and malignant pleural effusions (MPE) between September 2018 and December 2020. Differential and predominant leukocyte counts were performed using an automated XN-350 analyzer with a two-part differential count consisting of polymorphonuclear (PMN) and mononuclear (MN) leukocytes and a manual method with Wright-stained cytospin slides. We compared the two methods on cases of 109 PPEs, 50 TPEs, and 116 MPEs. Although the overall correlation between the two methods for differential leukocyte counts was excellent, there were etiologic variations; MPEs showed a lower correlation compared to PPEs and TPEs. Automated-PMN predominance almost corresponded to manual cytospin-neutrophilic predominance. In contrast, ~10% of the automated-MN predominance did not correspond with the cytospin-lymphocytic predominance. These discrepancies occurred most in the automated-MN% range of 51% to 60%, followed by 61% to 70%. The PMN% range ≥50% and <30% on the automated analysis reliably corresponds to the neutrophilic and lymphocytic predominance, respectively. However, the MN% range of 51% to 70% may not coincide with lymphocytic predominance on manual cytospin analysis. This range leaves the potential cause of exudative pleural effusions open.

Clinical application of an algorithm to screen for malignant cells in body fluids using an automated hematology analyzer

INTRODUCTION

The detection of malignant cells in body fluids (BF) with an automated hematology analyzer has been proposed as an alternative to morphological examination owing to its various advantages; however, its limitations have also been highlighted. In this study, we devised a practical algorithm to screen for malignant cells in BFs using an automated hematology analyzer.

METHODS

A total of 558 BF samples, including 232 cerebrospinal fluid (CSF) samples and 326 non-CSF samples, were consecutively collected. Thereafter, the results obtained using the BF mode of Sysmex XN-350 (Sysmex, Kobe, Japan) were compared with the cytological diagnosis. A cutoff was also established to screen for malignant cells using receiver operating characteristic (ROC) curve analysis based on the final clinical judgment.

RESULTS

The automated hematology analyzer showed a moderate correlation or good agreement with the existing cytological diagnosis. Further, of the ROC curves for detecting malignant cells, the absolute value of highly fluorescent cells on BF (HF-BF) in total body fluids showed the highest area under the curve (0.85 [95% confidence interval 0.82-88], p < .0001, Youden index >7×10⁶ /L, sensitivity 93%, and specificity 65%).

CONCLUSION

An automated hematology analyzer could function as a complement to cytological examination. We propose a practical and comprehensive algorithm for cytological examination that requires low- and high-resolution microscopy based on the absolute value of HF-BF in BF samples suspected of malignancy. This algorithm can more usefully detect malignant cells while taking advantage of the automated analyzer and cytological examination.