Cellular origin and diagnostic significance of high-fluorescent cells in cerebrospinal fluid detected by the XE-5000 hematology analyzer

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.

Automated Analysis of Cerebrospinal Fluid Cells Using Commercially Available Blood Cell Analysis Devices-A Critical Appraisal

The analysis of cells in the cerebrospinal fluid (CSF) is a routine procedure that is usually performed manually using the Fuchs–Rosenthal chamber and cell microscopy for cell counting and differentiation. In order to reduce the requirement for manual assessment, automated analyses by devices mainly used for blood cell analysis have been also used for CSF samples. Here, we summarize the current state of investigations using these automated devices and critically review their limitations. Despite technical improvements, the lower limit for reliable leukocyte counts in the CSF is still at approximately 20 cells/µL, to be validated depending on the device. Since the critical range for clinical decisions is in the range of 5–30 cells/µL this implies that cell numbers < 30/µL require a manual confirmation. Moreover, the lower limit of reliable erythrocyte detection by automated devices is at approximately 1000/µL. However, even low erythrocyte numbers may be of clinical importance. In contrast, heavily hemorrhagic samples from neurosurgery may be counted automatically at an acceptable precision more quickly. Finally, cell differentiation by automated devices provides only a rough orientation for lymphocytes, granulocytes and monocytes. Other diagnostically important cell types such as tumor cells, siderophages, blasts and others are not reliably detected. Thus, although the automation may give a gross estimate sufficient for the emergency room situation, each CSF requires a manual microscopy for cytological evaluation for the final report. In conclusion, although automated analysis of CSF cells may provide a first orientation of the cell profile in an individual sample, an additional manual cell count and a microscopic cytology are still required and represent the gold standard.

Automated cell count in body fluids: a review

Body fluid cell counting provides valuable information for the diagnosis and treatment of a variety of conditions. Chamber cell count and cellularity analysis by optical microscopy are considered the gold-standard method for cell counting. However, this method has a long turnaround time and limited reproducibility, and requires highly-trained personnel. In the recent decades, specific modes have been developed for the analysis of body fluids. These modes, which perform automated cell counting, are incorporated into hemocytometers and urine analyzers. These innovations have been rapidly incorporated into routine laboratory practice. At present, a variety of analyzers are available that enable automated cell counting for body fluids. Nevertheless, these analyzers have some limitations and can only be operated by highly-qualified laboratory professionals. In this review, we provide an overview of the most relevant automated cell counters currently available for body fluids, the interpretation of the parameters measured by these analyzers, their main analytical features, and the role of optical microscopy as automated cell counters gain ground.

Improving performance of recently introduced flow cytometry-based approach of malignant cell screening in serous cavity effusion

INTRODUCTION

Microscopy has been recognized as the "gold-standard" cellular analysis of serous cavity effusion. However, this method is time-consuming, labor-intensive, and requires accomplished skills. Here, we investigated the efficiency of hematology analyzer in screening malignant cells in serous cavity effusion.

METHODS

A total of 991 serous cavity effusion samples and 370 validation specimens collected from different departments were sent to the clinical laboratory for routine cell count using the automated hematology body fluid (BF) mode and exfoliative cytology simultaneously. High-fluorescent cells (HFCs) were measured as the relative count (HF%) and absolute count (HF#) by BF mode. Receiver operating characteristic curve analysis was combined with scattergram rules to screen malignant cells.

RESULTS

HF# and HF% in malignant samples (subgroup) were significantly higher than those in benign samples, and the HF# and HF% levels were different between ascites and pleural effusion (PE). The area under the curve values were also different between ascites and PE. Positive of malignant cells was very high when the ascites or PE sample touching Rule 1 positive and either Rule 2 negative or positive. The cutoff levels of HF# were 5.5 HFC/μL on the basis of Rules 1 and 2 negative, whereas 83.5 HFC/μL on the basis of Rule 1 negative but Rule 2 positive in ascites. By contrast, the cutoff levels of HF% were 0.55 HFC/100 WBC on the basis of Rules 1 and 2 negative, whereas 4.95 HFC/100 WBC on the basis of Rule 1 negative but Rule 2 positive in PE.

CONCLUSIONS

Serous cavity effusion will be increasingly analyzed using the automated hematology analyzer BF mode in the future because of its rapidness and convenience. The combined application of HFC with scattergram rules is a feasible and useful approach to screen malignant cells in serous cavity effusion.

Intrathecal IgM production is a strong risk factor for early conversion to multiple sclerosis

OBJECTIVES

To evaluate intrathecal immunoglobulin M (IgM) production, as compared to previously established risk factors, as risk factor for conversion from clinically isolated syndrome (CIS) to multiple sclerosis (MS) and to explore the association of intrathecal IgM production with onset age and radiologic and CSF findings in CIS/early MS.

METHODS

Comprehensive CSF data, including oligoclonal immunoglobulin G (IgG) bands (OCB) and calculated intrathecal IgM and IgG production, were collected in a prospective study of 150 patients with CIS/early MS with regular clinical and MRI assessments.

RESULTS

Intrathecal IgM production >0% occurred in 23.2% (33/142) of patients, who were on average 5 years younger at disease onset (p = 0.013) and more frequently had infratentorial lesions (18/32, 56.3%) than patients without intrathecal IgM production (33/104, 31.7%, p = 0.021). In multivariable Cox regression analyses, intrathecal IgM production in patients with a CIS (n = 93, median clinical and MRI follow-up 24 and 21 months) was strongly associated with conversion to MS according to the McDonald 2010 criteria (hazard ratio [95% confidence interval] 3.05 [1.45-6.44], p = 0.003) after adjustment for age (0.96 [0.93-1.00], p = 0.059), OCB (0.92 [0.33-2.61], p = 0.879), intrathecal IgG production (0.98 [0.48-1.99], p = 0.947), and radiologic evidence of dissemination in space (2.63 [1.11-6.22], p = 0.028).

CONCLUSION

Intrathecal IgM production is a strong independent risk factor for early conversion to MS and may thus represent a clinically meaningful marker for predicting future disease activity in patients with a CIS.

The diagnostic ability of high-fluorescent cells combined with carcinoembryonic antigen for malignant pleural effusion

INTRODUCTION

High-fluorescent cells (HFCs) that are detected with an automated hematology analyzer may be useful for the detection of tumor cells; however, the diagnostic ability of HFCs for differentiating malignant pleural effusion is limited. The aim of this study was to investigate the diagnostic value of the combined detection of HFCs with the tumor marker carcinoembryonic antigen (CEA) for the identification of malignant hydrothorax.

METHODS

A total of 115 pleural effusions were collected. HFCs, including the relative counts (HF-BF%) and absolute counts (HF-BF#), were analyzed using the BF mode of a Sysmex XN9000 hematology analyzer. Simultaneously, the CEA level from the same patient was measured by an electrochemiluminescence method. Receiver operating characteristic (ROC) curve analysis was employed to evaluate the diagnostic accuracy of HFCs separately or combined with CEA analysis for malignant diseases.

RESULTS

The levels of HF-BF#, HF-BF%, and CEA in the malignant effusion group were significantly higher than those in the benign control group. The diagnostic value of the HF-BF# and HF-BF% for malignant pleural effusion was low to moderate, and the area under the curve (AUC) was 0.663 and 0.715, respectively. The CEA detection showed a moderate diagnostic ability, and the AUC was 0.832. The AUC for the combined methods was 0.860 and 0.890, respectively. The cutoff levels of the HF-BF#, HF-BF%, and CEA levels were 29.5 × 10⁶ /L, 5.6/100 WBC, and 4.795 ng/mL, respectively.

CONCLUSIONS

The combined detection of high-fluorescent cells with the BF mode and CEA testing may be a good indication for malignancy.

Lack of harmonization in high fluorescent cell automated counts with body fluids mode in ascitic, pleural, synovial, and cerebrospinal fluids

INTRODUCTION

Cellular analysis in body fluids (BFs) provides important diagnostic information in various pathological settings. This study was hence aimed at comparing automated cell count obtained with Mindray BC-6800 (BC-BF) vs Sysmex XN-series (XN-BF) and evaluating other quantitative and qualitative information provided by these analyzers in ascitic (AF), pleural (PF), synovial (SF), and cerebrospinal (CSF) fluids.

METHODS

Three hundred and fifty-one samples (99 AFs, 45 PFs, 75 SFs, and 132 CSFs) were analyzed in parallel with BC-BF, XN-BF, and optical microscopy (OM). The study also included the assessment of diagnostic agreement among BC-BF, XN-BF, and OM.

RESULTS

The comparison of BC-BF vs XN-BF yielded slopes of Passing and Bablok regression always comprised between 0.9 and 1.0 except for EO-BF and HF-BF, whilst the intercepts ranged from -0.4 for MN-BF and 12.0 for PMN-BF. The bias was comprised between -103.3% and 67.1% for HF-BF and EO-BF, respectively. A significant bias was found for TC-BF, WBC-BF, HF-BF (negative bias) and for PMN-BF and EO-BF (positive bias). The agreement (Cohen's kappa) between XN-BF and BC-BF was always ≥0.7, ranging between 0.87 in CSFs and 0.94 in AFs, and that with OM was similar (ie, 0.85 and 0.96).

CONCLUSION

The cytometric analysis of BF samples using BC-BF and XN-BF is clinically favorable when appropriately combined with OM. Quantitative and qualitative parameters displayed optimal agreement, whilst instrument-specific cut-offs should be defined and implemented for HF-BF and EO-BF. Further efforts should be made for achieving better harmonization in cytometric analysis of BF samples.

Two-site evaluation of the diagnostic performance of the Sysmex XN Body Fluid (BF) module for cell count and differential in Cerebrospinal Fluid

INTRODUCTION

Cellular analysis in cerebrospinal fluid (CSF) provides important diagnostic information in many pathological settings. The aim of this two-site study was to evaluate the Sysmex XN Body Fluid mode (XN-BF) for cell analysis of CSF compared to light microscopy (LM).

METHODS

Two hundred and seven consecutive CSF samples were analyzed in parallel with XN-BF and LM. The study also included the estimation of the limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), carry-over and linearity of XN-BF module.

RESULTS

LoQ of white blood cells (WBC) was 3×10⁶  cells/L; linearity was good and carry-over negligible. XN-BF parameters were compared to LM for the following cell classes: total cells, WBC, polymorphonuclear (PMN), and mononuclear (MN) cells. The bias ranged from 1.3 to 15.2×10⁶  cells/L. The receiver operating characteristics curve analysis for WBC showed an area under the curve of 0.98, and the global diagnostic agreement was 95% at a cutoff of 5×10⁶  cells/L.

CONCLUSIONS

XN-BF provides rapid and accurate counts in clinically relevant ranges of CSF values, thus providing a valuable alternative to conventional LM analysis. However, microscopic review remains advisable in samples with abnormal cell counts or high fluorescent (HF-BF) cell parameter exceeding 5×10⁶  cells/L.

Evaluation of Sysmex XN-1000 High-Sensitive Analysis (hsA) Research Mode for Counting and Differentiating Cells in Cerebrospinal Fluid

OBJECTIVES

Counting cells in cerebrospinal fluid (CSF) using automated analyzers is generally problematic due to low precision at low cell numbers. To overcome this limitation, Sysmex (Kobe, Japan) developed the high-sensitive analysis (hsA) research mode specifically for counting cells in fluids that contain low cell counts. We evaluated this mode by counting RBCs, WBCs, and differentiated WBCs in CSF samples.

METHODS

We analyzed 248 CSF samples using the hsA mode and compared these results with those obtained using the manual counting method. We also evaluated the linearity, detection limits, carryover, and precision of the hsA mode.

RESULTS

Using the hsA mode, the lower limit of quantification for RBCs and WBCs was 10 and 2 cells/μL, respectively. Comparing the two methods revealed good agreement with respect to WBCs (y = 1.08x + 0.52), RBCs (y = 1.07x + 0.00), lymphocytes (y = 1.00x + 0.00), neutrophils (y = 1.05x + 0.00), and monocytes (y = 0.88x + 0.07). Regression analysis for samples containing low WBCs (<10 cells/μL) and low RBCs (<50 cells/μL) also had good agreement, although a slight positive bias was found for RBCs. Linearity was good (r(2) ≥ 0.99) for all parameters evaluated. Carryover was negligible and never exceeded 0.04%.

CONCLUSIONS

The XN hsA research mode provides reliable cell counts in CSF samples, even in samples containing low numbers of WBCs and RBCs.

Evaluation of Mindray BC-6800 body fluid mode for automated cerebrospinal fluid cell counting

Background:

Cellular analysis in cerebrospinal fluid (CSF) provides important diagnostic information in various medical conditions. The aim of this study was to evaluate the application of Mindray BC-6800 body fluid (BF) mode in cytometric analysis of CSF compared to light microscopy (LM).

Methods:

One hundred and twenty-nine consecutive CSF samples were analyzed by BC-6800-BF mode as well as by LM. The study also included limits of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), carryover and linearity.

Results

White blood cells LoQ was 4.0×10

Conclusions:

BC-6800-BF offers rapid and accurate counts in clinically relevant concentration ranges, replacing LM for most samples. However, in samples with abnormal cell counts or with abnormal white blood cell differential scattergrams the need to microscopic review for a correct clinical outcome remains.

Flow cytometry for the microscopy of body fluids in patients with suspected infection

Automating the microscopy of body fluids is challenging, due to the wider range and lower concentrations of cells in these fluids, as opposed to blood, while the viscous nature of some of these fluids can also be problematic. This review shows that there have been major improvements and that newer flow cytometers can have remarkably low limits of quantitation for WBCs. Accurate counting of RBCs is still problematic with many flow cytometers, but this is of no clinical significance. Many flow cytometers can give reasonably accurate WBC differential counts, but detection of eosinophils and neoplastic or other nucleated cells which are not blood cells can still be problematic, hence fail-safe measures are recommended. Cerebrospinal fluid is the most challenging body fluid as it requires the ability to count and differentiate WBCs down to a 'normal range', which is much lower than the diagnostic cut-off values used for serous fluids; precision at or around the cerebrospinal fluid WBC normal range is reduced even with the best flow cytometers, but manual microscopy is even less precise.

Detection of malignant cells in serous body fluids by counting high-fluorescent cells on the Sysmex XN-2000 hematology analyzer

INTRODUCTION

The body fluid mode of the Sysmex XN-2000 hematology analyzer differentiates cells into mononuclear and polymorphonuclear white blood cells (WBC) and high-fluorescent cells (HFC). The aim of this study was to evaluate the performance of the HFC count for detecting malignant cells in serous body fluids.

METHODS

Two-hundred and thirty serous fluids were analyzed on the Sysmex XN body fluid mode. HFC were measured as relative count (HFC/100 WBC) and absolute count (HFC/μL). All samples were microscopically screened on cytospin slides for the presence of malignant cells.

RESULTS

Malignant cells were found by microscopic examination in 49 of 230 samples (21.3%). Malignant samples contained significantly higher percentages (10.2 vs. 2.6/100 WBC) and absolute numbers (65 vs. 10/μL) of HFC than nonmalignant samples (P < 0.001). Areas under the ROC curve for relative and absolute HFC count were 0.69 and 0.77, respectively. A cutoff level of ≥17 HFC/μL showed the best performance to predict malignancy, with 88% sensitivity and 61% specificity.

CONCLUSION

As serous body fluids will be more analyzed on automated analyzers in the future, HFC count can be a useful tool to select samples for microscopic review. Microscopic evaluation should be performed if HFC values are above a certain threshold (e.g. ≥17 HFC/μL) or in case of clinical suspicion of malignancy.

Body fluid cellular analysis using the Sysmex XN-2000 automatic hematology analyzer: focusing on malignant samples

INTRODUCTION

The majority of previous studies on body fluid (BF) mode of automatic hematology analyzer used nonmalignant BF samples. Here, we evaluated the BF mode on the recently launched Sysmex XN for counting blood cells, especially for malignant samples.

METHODS

A total of 405 BF specimens including 125 malignant samples were analyzed using both the automated method and manual microscopy.

RESULTS

In non-cerebrospinal fluids (CSF) samples, there was an agreement between two methods for WBC, RBC, polymorphonuclear, and mononuclear cell counts (R(2)  = 0.96, 0.94, 0.88, and 0.88, respectively). CSF samples showed slightly poorer correlations than other fluids. Exclusion of malignant samples significantly improved correlations in non-CSF samples, but not in CSF samples. High fluorescence-BF (HF-BF) cells were identified significantly more frequently in malignant samples compared to benign samples (17.8 and 4.15/100 WBC, respectively; P < 0.001). Receiver operating characteristic curve analysis demonstrated an HF-BF cell AUC of 0.791 using a cutoff value of 6.9/100 WBC for detecting malignant samples.

CONCLUSION

The BF mode on the Sysmex XN could be an alternative method for the manual counts in the BF analysis with a few drawbacks. However, if a concentration of HF-BF cells is greater than the given threshold, microscopic examination should be subsequently performed.

Automated white blood cell counts in cerebrospinal fluid using the body fluid mode on the platform Sysmex XE-5000

BACKGROUND

The Sysmex XE-5000 offers automated quantification of red blood cells and white blood cells (WBCs) in body fluids, with differentiation of polymorphonuclear cells (PMNs) and mononuclear cells (MNCs).

METHODS

We evaluated automated WBC counting in cerebrospinal fluid (CSF) using the body fluid mode on the Sysmex XE-5000, comparing it with flow cytometry as the reference method, and also with manual counting by microscopy. Experimental analysis for linearity and limit of detection was performed by diluting isolated WBCs in cell-free CSF. To study the ability to discriminate between PMNs and MNCs, samples were spiked using MNCs separated from peripheral blood. Comparison of WBC counts between a counting chamber and the XE-5000 was performed for 198 CSF samples.

RESULTS

In the experimental set-up, within-run (CV 19%) and between-day imprecision (CV 15.3%) in quantitating total number of WBC on XE-5000 was acceptable for WBC counts ≥ 25 × 10(6)/L. Compared with expected cell counts, mean bias was + 2.6% for flow cytometry, + 5.5% for XE-5000 and - 73.2% for manual counting. Differentiation between PMNs and MNCs was in concordance with flow cytometry. In comparisons of clinical CSF samples, overall agreement between the XE-5000 and manual counting was observed in 81% of the samples, but mean difference in WBC differentiation was higher for PMN (51.1 × 10(6)/L) than for MNC (7.95 × 10(6)/L).

CONCLUSION

Despite limited precision at low WBC counts, XE-5000 could be a favourable alternative to the labour-intensive, time-consuming and less reliable manual counting and cuts turnaround times in routine CSF-based diagnosis.