Two cases with discrepancy in the quantitative cytological assessment of cerebrospinal fluid in neonatal samples using light microscopy in comparison with Sysmex XN-1000

We present two cases from the neonatal department with cerebrospinal fluid examination. We revealed a striking discrepancy in polymorphonuclear (PMN) and mononuclear (MN) cell counts using conventional light microscopy in comparison with automated analyzer Sysmex XN-1000 (PMNs - 13 vs. 173x106/L, MNs - 200 vs. 67x106/L in case 1 and PMNs - 13 vs. 372x106/L, MNs - 411 vs. 179x106/L in case 2). We revealed the dominant presence of hemosiderophages in both cases in cytospin slide. Even though Sysmex XN-1000 offers fast examination with a low sample volume, there is possibility of misdiagnosis, with negative impact on the patient.

Performance evaluation of the new Sysmex XR-Series haematology analyser

Background

The new XR-Series haematology analyser from Sysmex provides increased throughput and automation, along with a new reagent in WDF channel for optimised WBC differential.

Methods

An analytical performance study for the XR analyser was conducted to evaluate the WDF channel parameters in comparison to the instrument specifications. Additionally, 7460 samples were measured on XR and XN analysers to compare selected parameters and flags, and 930 randomly selected samples were further evaluated with microscopy.

Results

All investigated aspects of the analytical performance study for the XR fell within the manufacturer specifications. The correlation coefficients between the two systems for the parameters tested were greater than 0.983 for the main CBC and DIFF parameters, greater than 0.909 for the Extended Inflammation Parameters, and greater than 0.932 for the parameters used in the workflow rulesets of the Extended IPU. Similarly high sensitivities for the detection of abnormal cells were observed for the 'Blasts/Abn Lympho?' flag (XN: 100%, XR: 99.0%) and WPC abnormal flags ('Blasts?' or 'Abn Lympho?') (XN: 97.0%, XR: 96.0%). XN with WPC channel had a 26% reduction of false positive smears compared to XR with 22% reduction, a statistically non-significant difference.

Conclusion

The XR analyser had very good analytical performance, and highly comparable results to the predecessor XN analyser in all investigated parameters, flags and workflow aspects.

Hematocrit-Independent Sampling Enables White Blood Cell Counts from Patterned Dried Blood Spot Cards

The accurate and efficient measurement of white blood cell (WBC) counts is vital for monitoring general patient health and can aid in the diagnosis of a range of possible infections or diseases. Even with their importance universally acknowledged, access to WBC counts is largely limited to those with access to phlebotomists and centralized clinical laboratories, which house the instruments that perform the tests. As a result, large populations of people (e.g., those that are home-bound or live in remote locations) lack facile access to testing. Dried blood spot (DBS) cards are often used to bridge these gaps in access to testing by offering the ability to collect blood at home for ambient shipping to laboratories. However, it is well understood that these cards, which are prepared from cellulose cardstocks without further modification, suffer from variabilities in accuracy and precision due to uncontrolled sample spreading and hematocrit effects, which have hindered their use to determine WBC counts. In this paper, we present a method to obtain an accurate WBC count using a patterned dried blood spot (pDBS) card, which comprises collection zones that meter volumes of dried blood. Using an input volume of 75 μL of whole blood, we demonstrate that, unlike the gold standard DBS card (Whatman 903), our pDBS design allows for the collection of replicate zones containing a reproducible, average volume of dried blood (12.1 μL, 7.8% CV) over the range of hematocrits from 25 to 55%. We then used qPCR to quantify the 18S rRNA gene to determine WBC counts from the volumes of blood that are metered in pDBS zones. We observe that WBC counts generated from our method are comparable to those measured with a HemoCue point-of-care WBC analyzer. Our approach to using pDBS cards as a blood collection device has the potential to support at-home sampling and other patient populations that need WBC counts but lack access to clinical facilities.

Toward five-part differential of leukocytes based on electrical impedances of single cells and neural network

The five-part differential of leukocytes plays key roles in the diagnosis of a variety of diseases and is realized by optical examinations of single cells, which is prone to various artifacts due to chemical treatments. The classification of leukocytes based on electrical impedances without cell treatments has not been demonstrated because of limitations in approaches of impedance acquisition and data processing. In this study, based on treatment-free single-cell impedance profiles collected from impedance flow cytometry leveraging constriction microchannels, two types of neural pattern recognition were conducted for comparisons with the purpose of realizing the five-part differential of leukocytes. In the first approach, 30 features from impedance profiles were defined manually and extracted automatically, and then a feedforward neural network was conducted, producing a classification accuracy of 84.9% in the five-part leukocyte differential. In the second approach, a customized recurrent neural network was developed to process impedance profiles directly and based on deep learning, a classification accuracy of 97.5% in the five-part leukocyte differential was reported. These results validated the feasibility of the five-part leukocyte differential based on label-free impedance profiles of single cells and thus provide a new perspective of differentiating white blood cells based on impedance flow cytometry.

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.

Serous body fluid evaluation using the new automated haematology analyser Mindray BC-6800Plus

OBJECTIVES

Cellular analysis of body fluids (BF) has clinical relevance in several medical conditions. The objective of this study is twofold: (1) evaluate the analytical performance of the BF mode of Mindray BC-6800 Plus compared to manual counts under microscopy and (2) analyse if the high-fluorescent cell counts provided by the analyser (HF-BF) are useful to detect malignancy.

METHODS

A total of 285 BF was analysed: 250 corresponding to patients without neoplasia and 35 to patients with malignant diseases. Manual differential counts were performed in BF with ≥250 cells/μL. Percentages and absolute counts were obtained on the BC-6800Plus for total nucleated cells (TC-BF), mononuclear, polymorphonuclear and HF-BF. Statistical analysis was performed using Mann-Whitney U-test, Spearman's correlation, Passing-Bablok regression, Bland-Altman graph and ROC curve.

RESULTS

To compare manual and automatic total cell counts, samples were divided in three groups: <250, 250-1,000 and >1,000 cells/μL. Correlation was good in all cases (r=0.72, 0.73 and 0.92, respectively) without significant differences between both methods (p=0.65, 0.39 and 0.30, respectively). The concordance between methods showed values of 90%. Considering malignant samples, median HF-BF values showed significant higher values (102 cells/μL) with respect to non-malignant (4 cells/μL) (p<0.001). The cut-off value of 8.5 HF-BF/μL was able to discriminate samples containing malignant cells showing sensitivity and specificity values of 89 and 71%, respectively. Considering both, HF-BF and TC-BF values, sensitivity and specificity values were 100 and 53%, respectively.

CONCLUSIONS

This study reveals that the Mindray BC-6800Plus offers an accurate and acceptable performance, showing results consistent with the manual method. It is recommended to consider both HF-BF and TC-BF values for the screening of the microscopic evaluation to ensure the detection of all malignant samples.

Septic Arthritis Complicating Arthroscopic Anterior Cruciate Ligament Reconstruction: An Experience from a Tertiary-Care Hospital

Background

Septic arthritis (SA) of the knee following anterior cruciate ligament reconstruction (ACLR) is considered a catastrophic complication in terms of reduced or loss function of the involved joint. The aims of this study were to gauge the incidence, risk factors, and causative organisms of SA after ACLR.

Methods

We conducted a retrospective review of 836 patients who underwent primary ACLR at our institution from October 2018 to September 2021. Patients’ demographics, onset of presentation, clinical symptoms, laboratory findings, and management details were obtained from patients’ electronic medical records.

Results

Out of the 836 primary ACLRs, 12 were complicated with SA (1.43%). Independent risk factors associated with SA included age (OR; 11.12, 95% CI; 1.3–94.97), obesity (OR; 8.51, 95% CI; 1.02–71.13), and diabetes mellitus (OR; 12.58, 95% CI; 2.39–66.3). Staphylococcus aureus was the most frequent culprit organism (66.7%), followed by Streptococcus species (25%), and Pseudomonas aeruginosa (8.3%). No fungal, mycobacterial, or polymicrobial growth were recovered from synovial fluid cultures. All of the infected cases underwent arthroscopic joint lavage and debridement in the operating room followed by intravenous antibiotics. Graft removal was not done in any of the involved patients, with eradication of infection in all cases.

Conclusion

SA after ACLR is uncommon, with S. aureus identified in about two-thirds of the patients. Prompt diagnosis and treatment are crucial to avoid graft loss and arthritis-associated joint damage. Orthopedic surgeons should consider rigorous implementation of infection control strategies to minimize the incidence of this devastating morbidity.

Performance evaluation of automated cell counts compared with reference methods for body fluid analysis

OBJECTIVES

Cellular analysis of body fluids (BFs) can assist clinicians for the diagnosis of many medical conditions. The aim of this work is the evaluation of the analytical performance of the UF-5000 body fluid mode (UF-BF) analyzer compared to the gold standard method (optical microscopy, OM) and to XN-1000 (XN-BF), another analyzer produced by the same manufacturer (Sysmex) and with a similar technology for BF analysis.

METHODS

One hundred BF samples collected in K₃EDTA tubes were analyzed by UF-BF, XN-BF and OM. The agreement was evaluated using Passing and Bablok regression and Bland-Altman plot analysis. The receiver operating characteristic (ROC) curves were selected for evaluating the diagnostic agreement between OM classification and UF-BF parameters.

RESULTS

Comparison between UF-BF and OM, in all BF types, showed Passing and Bablok's slope comprised between 0.99 (polymorphonuclear cells count, PMN-BF) and 1.39 (mononuclear cells count, MN-BF), the intercepts ranged between 26.47 (PMN-BF parameter) and 226.80 (white blood cell count). Bland-Altman bias was comprised between 7.3% (total cell count, TC-BF) and 52.9% (MN-BF). Comparison between UF-BF and XN-BF in all BF showed slopes ranged between 1.07 (TC-BF and PMN-BF) and 1.16 (MN-BF), intercepts ranged between 8.30 (PMN) and 64.78 (WBC-BF). Bland-Altman bias ranged between 5.8 (TC-BF) and 21.1% (MN-BF). The ROC curve analysis showed an area under the curve ranged between 0.9664 and 1.000.

CONCLUSIONS

UF-BF shows very good performance for the differential counts of cells in ascitic, pleural and synovial fluids and therefore it is useful to screen and count cells in this type of BF.

A microfluidic cytometer for white blood cell analysis

Despite the wide use of cytometry for white blood cell classification, the performance of traditional cytometers in point-of-care testing remains to be improved. Microfluidic techniques have been shown with considerable potentials in the development of portable devices. Here we present a prototype of microfluidic cytometer which integrates a three-dimensional hydrodynamic focusing system and an on-chip optical system to count and classify white blood cells. By adjusting the flow speed of sheath flow and sample flow, the blood cells can be horizontally and vertically focused in the center of microchannel. Optical fibers and on-chip microlens are embedded for the excitation and detection of single-cell. The microfluidic chip was validated by classifying white blood cells from clinical blood samples.

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.

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

We evaluated the capacity of the XN-350 instrument to analyze 3 different types of body fluid samples under "body fluid mode."The performance of XN-350 was evaluated in terms of precision, carryover, limit of blank, limit of detection, limit of quantification, and linearity. Cell enumeration and differential data produced by the XN-350 were compared to manual chamber counting results in 63 cerebrospinal fluid (CSF), 51 ascitic fluid, and 51 pleural fluid (PF) samples. Comparisons between XN-350 versus Cytospin data were also performed in PF samples.The precision, carry-over, limit of blank, and linearity of the XN-350 were acceptable. The limits of detection for white blood cells (WBCs) and red blood cells were 1.0/μL, and 1,000.0/μL, respectively; the corresponding limits of quantitation (LOQs) were 5.0/μL and 2,000.0/μL, respectively. The XN-350's cell enumeration and differential counting correlated well with those of manual chamber counting for all 3 sample types (except for differential counting in CSF samples), particularly parameters involving monocytes (r = 0.33) and mononuclear cells (MO- body fluid [BF]; r = 0.26), as well as total cell (TC-BF) enumeration (r = 0.50) and WBC-BF (r = 0.50) in PF samples. The MO-BF in CSF samples differed significantly from manual chamber counting results, but neither TC-BF nor WBC-BF in PF samples did. The XN-350 also showed good correlations with Cytospin analyses for differential counting of neutrophils, lymphocytes, and monocytes in PF samples. The differential counting of eosinophils via the XN-350 and Cytospin were not significantly correlated, but the difference between them was not significant.The XN-350 is an acceptable alternative to manual fluid analysis. Samples with low cellularity around the LOQ should be checked manually. Moreover, manual differential counting should be performed on CSF samples, particularity those with low cell numbers.

The Sysmex XN-L (XN-350) hematology analyzer offers a compact solution for laboratories in niche diagnostics

INTRODUCTION

In 2015, Sysmex launched a new series of hematology analyzers (XN-L Series) designed to fulfill the needs of niche laboratories in areas such as pediatrics, dialysis, neurology, and oncology while providing a compact solution. In this study, we evaluate the whole blood and body fluid modes of one of these analyzers, the XN-350.

METHODS

A total of 300 residual EDTA samples were measured on the XN-350 in whole blood mode and the XN-1000 to evaluate method comparison, flagging sensitivity, repeatability, reproducibility, linearity, carryover, and stability. In addition, 191 samples were obtained and processed in body fluid mode which included, cerebrospinal fluid (CSF), continuous ambulatory peritoneal dialysis (CAPD), ascites, synovial, and pleural fluid to perform method comparison, repeatability, reproducibility, linearity, limit of quantitation, and carryover studies.

RESULTS

Strong agreement was shown between the XN-350 and XN-1000 for both whole blood and body fluid modes in results and flagging. Linearity results in both modes on the XN-350 showed a high R² value (>.99). For WBC, RBC, HGB, and PLT, the carryover results were well within the predetermined criteria of ≤0.5% for whole blood and ≤0.3% for CSF. Repeatability and reproducibility were acceptable for both modes, and there were no significant deviations present in stability for whole blood. In addition, there was high agreement in all body fluid types evaluated.

CONCLUSION

The performance of the XN-350 is comparable to the XN-1000 in both whole blood and body fluid modes, making it a reliable alternative to larger analyzers for smaller, niche laboratories.

Laboratory testing of extravascular body fluids: National recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine. Part II - Synovial fluid

Joint diseases are conditions with an often progressive and generally painful nature affecting the patient's quality of life and, in some cases, requiring a prompt diagnosis in order to start the treatment urgently. Synovial fluid (SF) laboratory testing is an important part of a diagnostic evaluation of patients with joint diseases. Laboratory testing of SF can provide valuable information in establishing the diagnosis, be a part of a patient's follow-up and treatment with the purpose of improving the patient's health and quality of life. Synovial fluid laboratory testing is rarely performed in Croatian medical biochemistry laboratories. Consequently, procedures for SF laboratory testing are poorly harmonized. This document is the second in the series of recommendations prepared by the members of the Working group for extravascular body fluid samples of the Croatian Society of Medical Biochemistry and Laboratory Medicine. It addresses preanalytical, analytical, and postanalytical issues and the clinical significance of tests used in SF laboratory testing with the aim of improving the value of SF laboratory testing in the diagnosis of joint diseases and assisting in the achievement of national harmonization. It is intended for laboratory professionals and all medical personnel involved in synovial fluid collection and testing.

Peripheral leukocyte counts vary with lipid levels, age and sex in subjects from the healthy population

BACKGROUND AND AIMS

Disorders in blood lipid metabolism and leukocyte-mediated inflammation are considered the main mechanisms of the pathogenesis of atherosclerosis. This study aims to show whether and how peripheral leukocyte counts are associated with serum lipid levels.

METHODS

This is a cross-sectional study of 175,079 subjects from the healthy population.

RESULTS

Age and sex are two key factors dictating the relationship between peripheral leukocyte counts and serum lipid levels. The log-transformed level of triglycerides (LnTG) was positively associated with all leukocyte counts in males except monocyte count in younger subjects. LnTG was positively associated with total leukocyte count in females regardless of age, and it was positively associated with lymphocyte and monocyte counts and neutrophil count only in elderly and young women, respectively. Total cholesterol levels were positively associated with total leukocyte, neutrophil and lymphocyte counts only in young males and with lymphocyte counts only in elderly women. LDL-C was negatively associated with monocyte count in males regardless of age; by contrast, it was positively associated with total leukocyte and lymphocyte counts in females regardless of age range and neutrophil and LnEosinophil counts only in young women. HDL-C was negatively associated with total leukocyte, lymphocyte and monocyte counts in both young men and young women; was negatively associated with monocyte count in elderly men and women; and was negatively associated with LnEosinophil count only in older men.

CONCLUSIONS

Peripheral leukocyte counts are extensively associated with serum lipid levels, with patterns differing by sex, age, lipid and leukocyte subset.

White blood cell counting at point-of-care testing: A review

White blood cells, which are also called leukocytes, are found in the immune system that are involved in protecting the body against infections and foreign invaders. Conventional methods of leukocyte analysis provide valuable and accurate information to medical specialists. Analyzing and diagnosing of a disease requires a combination of multiple biomarkers, in some cases, however, such as personal health care, this will occupy some medical resources and causes unnecessary consumption. Traditional method (such as flow cytometer) for WBC counting is time and labor consuming. Compared to gold standard (flow-based fraction/micropore filtration) or improved filtration methods for WBC counting, this is still a lengthy and time consuming process and can lead to membrane fouling due to the rapid accumulation of biological materials. Therefore, the analysis of WBC counts requires more compact and efficient equipment. The microfluidic technologies, powered by different field (force, thermal, acoustic, optical, magnetic) and other methods for leukocyte counting and analysis, are much cost-efficient and can be used in in-home or in resource-limited areas to achieve Point-of-Care (POC). In this review, we highlight the mainstream devices that have been commercialized and extensively employed for patients for WBC counting, Next, we present some recent development with regards to leucocyte counting (mainly microfluidic technologies) and comment on their relative merits. We aim to focus and discuss the possibility of achieving POC and help researchers to tackle individual challenges accordingly. Finally, we offer some technologies in addition to previous detection devices, such as image recognition technology and cloud computing, which we believe have great potential to further promote real-time detection and improve medical diagnosis.

Performance Evaluation of Body Fluid Cellular Analysis Using the Beckman Coulter UniCel DxH 800, Sysmex XN-350, and UF-5000 Automated Cellular Analyzers

BACKGROUND

Automated cellular analyzers are expected to improve the analytical performance in body fluid (BF) analysis. We evaluated the analytical performance of three automated cellular analyzers and established optimum reflex analysis guidelines.

METHODS

A total of 542 BF samples (88 cerebrospinal fluid [CSF] samples and 454 non-CSF samples) were examined using manual counting and three automated cellular analyzers: UniCel DxH 800 (Beckman Coulter), XN-350 (Sysmex), and UF-5000 (Sysmex). Additionally, 2,779 BF analysis results were retrospectively reviewed. For malignant cell analysis, the receiver operating characteristic (ROC) curve was used, and the detection of high fluorescence-BF cells (HF-BFs) using the XN-350 analyzer was compared with cytology results.

RESULTS

All three analyzers showed good agreement for total nucleated cell (TNC) and red blood cell (RBC) counts, except for the RBC count in CSF samples using the UniCel DxH 800. However, variable degrees of differences were observed during differential cell counting. For malignant cell analysis, the area under the curve was 0.63 for the XN-350 analyzer and 0.76 for manual counting. We established our own reflex analysis guidelines as follows: HF-BFs <0.7/100 white blood cells (WBCs) is the criterion for quick scans with 100× magnification microscopic examination as a rule-out cut-off, while HF-BFs >83.4/100 WBCs or eosinophils >3.8% are the criteria for mandatory double check confirmation with 1,000× magnification examination.

CONCLUSIONS

The three automated analyzers showed good analytical performances. Application of reflex analysis guidelines is recommended for eosinophils and HF-BFs, and manual confirmation is warranted.

Two-site evaluation of a new workflow for the detection of malignant cells on the Sysmex XN-1000 body fluid analyzer

INTRODUCTION

The presence of high fluorescent cells (HF-BF) on the Sysmex XN-1000 hematology analyzers has gained interest regarding the prediction of malignant cells in body fluids, but lacks sensitivity. We aimed to increase this sensitivity by combining HF-BF value, automated results, and clinical information.

METHODS

We evaluated a new workflow for the management of body fluids in the hematology laboratory, including the HF-BF criterion and clinical information. In two laboratories, 1623 serous fluids were retrospectively analyzed on the XN-1000 BF mode. All samples were morphologically screened for malignant cells. Optimal HF-BF cutoffs were determined to predict their presence. Thereafter, the added value of clinical information was evaluated. Other reflex testing rules (eosinophilic count >5% and presence of the WBC Abnormal Scattergram flag) were also used to refine our workflow.

RESULTS

Optimal HF-BF cutoffs in the two hematology centers were 108 and 45 cells/µL, yielding a sensitivity/specificity of 66.7/93.6% and 86.8/66.6% for malignant cell detection. When adding clinical information, sensitivity/specificity evolved to 100.0/68.9% and 100.0%/not determined. Of 104 samples containing malignant cells, 97 had positive clinical information; the remainder had a HF-BF > cutoff.

CONCLUSION

Combining clinical information and HF-BF reached 100% sensitivity for malignant cell detection in body fluid analysis. Lack of robustness of the optimal HF-BF cutoff deserves the use of local cutoffs. Rapid automated results reporting from the XN-1000 BF mode are also feasible in clinical practice. Prospective evaluation of the workflow is needed before its implementation in clinical practice.

Laboratory testing of extravascular body fluids: National recommendations on behalf of the Croatian Society of Medical Biochemistry and Laboratory Medicine. Part I - Serous fluids

Extravascular body fluids (EBF) analysis can provide useful information in the differential diagnosis of conditions that caused their accumulation. Their unique nature and particular requirements accompanying EBF analysis need to be recognized in order to minimize possible negative implications on patient safety. This recommendation was prepared by the members of the Working group for extravascular body fluid samples (WG EBFS). It is designed to address the total testing process and clinical significance of tests used in EBF analysis. The recommendation begins with a chapter addressing validation of methods used in EBF analysis, and continues with specific recommendations for serous fluids analysis. It is organized in sections referring to the preanalytical, analytical and postanalytical phase with specific recommendations presented in boxes. Its main goal is to assist in the attainment of national harmonization of serous fluid analysis and ultimately improve patient safety and healthcare outcomes. This recommendation is intended to all laboratory professionals performing EBF analysis and healthcare professionals involved in EBF collection and processing. Cytological and microbiological evaluations of EBF are beyond the scope of this document.

Clinical training and validation of the LeukoScope: a low-cost, point-of-care device to perform white blood cell and neutrophil counts

A white blood cell (WBC) count with partial differential is an important clinical laboratory test. However, current methods to perform a WBC count and differential are difficult to use at the point of care or too expensive for use in low-resource settings. To meet this need, we developed the LeukoScope: a low-cost system to measure a WBC and neutrophil count from a single drop of blood at the point of care. The LeukoScope is battery powered and has a sample-to-answer time of <5 minutes. A drop of blood from a finger stick is added to a LeukoScope sample cartridge where pre-dried acridine orange fluorescently stains WBCs. The cartridge is then inserted into the LeukoScope reader where a portable fluorescence microscope captures a color image of the sample, which is analyzed to report results to the user. The LeukoScope system was tested at the point of care using fingerprick samples collected from 105 general oncology patients in Houston, TX. Performance of the LeukoScope was compared to that of a HemoCue WBC DIFF performed using the same fingerprick sample; clinical laboratory analysis of a venous blood draw was used as the gold standard in all cases. Bland-Altman analysis showed that the LeukoScope and HemoCue WBC DIFF had similar accuracy for measurement of WBC and neutrophil counts as compared to the gold standard. Seven out of eight patients with abnormal WBC count values were correctly identified using the LeukoScope, while six out of eight were correctly identified using the HemoCue WBC DIFF. Five out of six patients with abnormal neutrophil counts were correctly identified using the LeukoScope, while six of six were correctly identified using the HemoCue WBC DIFF.

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.

Cerebrospinal fluid monocytes in bacterial meningitis, viral meningitis, and neuroborreliosis

OBJECTIVE

Cerebrospinal fluid (CSF) leukocytes analysis is commonly used to diagnose meningitis and to differentiate bacterial from viral meningitis. Interpreting CSF monocytes can be difficult for physicians, especially in France where lymphocytes and monocytes results are sometimes pooled.

PATIENTS AND METHODS

We assessed SF monocytes in patients presenting with microbiologically confirmed meningitis (CSF leukocyte count>10/mm³ for adults or >30/mm³ for children<2 months), i.e. bacterial meningitis (BM), viral meningitis (VM), and neuroborreliosis (NB).

RESULTS

Two-hundred patients (82 BM, 86 VM, and 32 NB) were included. The proportions of monocytes were higher in VM (median 8%; range 0-57%) than in BM (median 5%; range 0-60%, P=0.03) or NB (median 5%; range 0-53%, P=0.46), with a high value overlap between conditions.

CONCLUSION

CSF monocytes should not be used to discriminate BM from VM and NB because of value overlaps.

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.

Continuous ambulatory peritoneal dialysis, ascitic and pleural body fluids evaluation with the Mindray BC-6800 hematology analyzer

BACKGROUND

Accurate evaluation of hematology analyzers is recommended before these devices can be broadly introduced for the routine testing of continuous ambulatory peritoneal dialysis (CAPD), ascitic, and pleural fluids.

METHODS

We evaluated the performance of Mindray BC-6800 for white blood cell (WBC) and differential cell count in 50 CAPD, 60 ascitic and 40 pleural compared with manual microscopy. Within-run precision, limit of blank (LoB), limit of detection (LoD), limit of quantitation (LoQ), and carryover were assessed.

RESULTS

The Passing-Bablok regression in all fluids showed the following equations: y_WBC =1.05x+3.31 (95%CI slope 0.95 to 1.12; intercept -0.25 to 5.52); y_MN =0.85x+15.63 (95%CI slope 0.72 to 1.05; intercept -24.18 to 84.47); and y_PMN =1.21x+13.37 (95%CI slope 1.03 to 1.35; intercept 4.00 to 32.47) with bias 78 cells/μL. The AUC for clinical PMN cut-off was 0.88 (95%CI: 0.77 to 0.98). In ascitic, pleural, and CAPD fluids the AUC for clinical PMN cut-off were 0.88 (95%CI: 0.63 to 1.00), 0.83 (95%CI: 0.68 to 0.99), and 1.00 (95%CI: 1.00 to 1.00) respectively. CV ranged from 3%-34%. LoB of 3 cell/μL was verified. LoD and LoQ reported the same result (8 cells/μL). Carry over never exceeded 0.05%.

CONCLUSION

The effectiveness of BC-6800 to categorize cells from different body fluids was not compromised by the slight positive bias observed. This conclusion is supported by the high AUC and agreement between the automated method and the reference method. The results show that BC-6800 offers rapid, accurate, and reproducible results for clinical management of CAPD, ascitic, and pleural fluids.

Higher positive identification of malignant CSF cells using the cytocentrifuge than the Suta chamber

ABSTRACT Objective To define how to best handle cerebrospinal fluid (CSF) specimens to obtain the highest positivity rate for the diagnosis of malignancy, comparing two different methods of cell concentration, sedimentation and cytocentrifugation. Methods A retrospective analysis of 411 CSF reports. Results This is a descriptive comparative study. The positive identification of malignant CSF cells was higher using the centrifuge than that using the Suta chamber (27.8% vs. 19.0%, respectively; p = 0.038). Centrifuge positively identified higher numbers of malignant cells in samples with a normal concentration of white blood cells (WBCs) (< 5 cells/mm3) and with more than 200 cells/mm3, although this was not statistically significant. There was no lymphocyte loss using either method. Conclusions Cytocentrifugation positively identified a greater number of malignant cells in the CSF than cytosedimentation with the Suta chamber. However, there was no difference between the methods when the WBC counts were within the normal range.

Cell Population Data and reflex testing rules of cell analysis in pleural and ascitic fluids using body fluid mode on Sysmex XN-9000

BACKGROUND

Although optical microscopy (OM) remains the reference technique for analysis of ascitic (AF) and pleural (PF) fluids, novel hematological analyzers are equipped with modules for body fluid (BF) analysis. This study was aimed to analyze the performance of XN-BF module in Sysmex XN-9000, and to develop validation rules for automated cell counts in BFs.

METHODS

The evaluation of XN-BF module included assessment of carryover, Limit of Blank (LoB), Limit of Detection (LoD), Limit of Quantitation (LoQ), linearity, data comparison with OM, and development of rules for assisting the validation of automated analysis of BFs and activating reflex testing.

RESULTS

The carryover was negligible. The LoB, LoD, LoQ and linearity were always excellent. The comparison with OM was characterized by Pearson's correlations ranging from r=0.50 to r=0.99 (p<0.001), modest bias and high diagnostic concordance (Area Under the Curve between 0.85 and 0.99). The use of instrument-specific cut-offs further increased diagnostic concordance. The implementation of reflex testing rules based on XN-BF data increased sensitivity and specificity of BFs classification to 0.98 and 0.95.

CONCLUSIONS

Our results suggest that the XN-BF module on Sysmex-9000 may be a suitable alternative to OM for screening BF samples, especially when specific validation rules are used.