Performance evaluation of the automated nucleated red blood cell count of five commercial hematological analyzers

Anaemia in South American camelids - an overview of clinical and laboratory diagnostics

South American camelids (SACs) play an increasing role in veterinary care in Europe. Many alpacas or llamas presented to veterinarians suffer from anaemia, regularly with a packed cell volume (PCV) below 0.10 l/l, which is a life-threatening condition for the animals. This review article presents clinical and laboratory diagnostic tools for the diagnosis of anaemia in SACs. Clinical identification of anaemic animals can be performed by assessing the FAMACHA© score and the Body Condition Score (BCS), since anaemia in alpacas and llamas correlates with pale mucous membranes and a lowered BCS. Haematological examination of a blood sample can provide a more differentiated diagnosis of anaemia in SACs. A common finding is regenerative anaemia with an increased number of reticulocytes that is often caused by blood loss due to Haemonchus contortus. Changes in a blood smear from an alpaca or llama with regenerative anaemia may include normoblasts (nucleated red blood cells), anisocytosis, poikilocytosis, polychromasia, Howell-Jolly bodies or basophilic stippling. Furthermore, non-regenerative anaemia, often caused by trace element deficiency or cachexia, can also occur.

Comparison Evaluation of Automated Nucleated Red Blood Cell Enumeration by Sysmex XN 1000 in Comparison With Microscopic Reference in Children Under 1 Year

BACKGROUND

In newborns, elevated nucleated red blood cell (NRBC) levels can be associated with enhanced erythropoietic stress and might be predictive for adverse outcome. Also, the presence of NRBC in peripheral blood might lead to erroneous enumeration results of white blood cells in automated hematology analyzers. We aimed to assess the comparability of the Sysmex XN 1000 to manual slide reviews and correlation of NRBC with inflammation markers.

METHODS

Specimens of 3397 children under 1 year were compared by automated and microscopic NRBC enumeration. Additionally, potential correlations between NRBC and age and inflammation markers were examined.

RESULTS

Overall, there was good correlation (r = 0.97) between automated (range: 0%-3883%) and microscopic enumeration (range: 0%-3694%) of NRBC with high comparability up to a NRBC value of 200% and an increase in the variation between the two methods with increasing NRBC numbers. When 94 samples with ≤ 200% NRBC and ≥ 30% divergence between methods were separately reanalyzed with respect to overlapping cell populations in their scattergrams, Sysmex would have generated unrecognized incorrect automated results in 47 samples, corresponding to 1.4% of total study samples. NRBC counts were negatively correlated to age, but not to inflammation markers.

CONCLUSION

Sysmex XN 1000 is highly precise in the enumeration of NRBC in children under 1 year up to counts of 200% and might replace time-intense manual counting in routine diagnostics. In the setting of neonatal and intensive care diagnostics, microscopic control and supervision of scattergrams are highly recommended for any automated NRBC enumeration processes.

Frequency of Nucleated Red Blood Cells in the Peripheral Blood of ICU-Admitted Patients

Background Nucleated red blood cells (NRBCs) are not normally found in the peripheral blood of normal healthy individuals. The presence of NRBCs on an adult peripheral blood smear indicates that there is an extremely high demand for the bone marrow to manufacture RBCs and that immature red blood cells are being released into the bloodstream. Anemia, myelofibrosis, thalassemia, miliary tuberculosis, malignancies of the bone marrow (myelomas, leukemias, lymphomas), and prolonged hypoxemia are a few possible pathogenic reasons. Critically ill patients who have NRBCs have a high mortality rate and a worse prognosis.

OBJECTIVE

To evaluate the clinical significance of NRBCs in the peripheral blood of critically ill patients admitted to the ICU to find a cut-off to predict mortality.

MATERIALS AND METHODS

A cross-sectional study was carried out over a period of six months September 1, 2020, to March 31, 2021, in Lahore, Pakistan. A total of 800 critically ill patients of both sexes in the age group of 18-70 years were included. Patients younger than 18 years and patients who underwent surgery were excluded. A quantity of 3 ml of whole blood sample in an ethylenediamine tetraacetic acid (EDTA) vial from each patient was run on SYSMEX XN-9000 (Sysmex Corporation, Kobe, Hyogo, Japan) and the results were reviewed on peripheral smears.

RESULTS

The incidence of NRBCs in ICU-admitted patients was 62.5% (500/800). The total number of NRBC-positive patients recovering after the treatment was 364 (72.8%). The overall mortality of NRBC-positive patients was 30% (150/500). It was significantly higher (p<0.001) than that of NRBC-negative patients (14%; 44/300). During treatment, the highest mortality rate was seen in patients due to malignancy (100%), followed by sepsis (58.8%). It was observed that the disease pattern and number of NRBCs were significantly different (p<0.001) among all disease groups. However, there was no statistically significant difference in NRBCs on the basis of gender (p >0.05). In our study, a cutoff of NRBCs of 2.50 showed a high risk of mortality with a sensitivity of 91%.

CONCLUSION

The presence of NRBCs may predict mortality in critically ill ICU-admitted patients. Their presence in the blood may be regarded as a marker of severity suggesting a high risk of ICU death.

Full-field hemocytometry. Forty years of progress seen through Clinical and Laboratory Hematology and the International Journal of Laboratory Hematology

The extraordinary advances in clinical hematology, biology, and oncology in the last decades would not have been possible without discovering how to identify and count the cells circulating in the blood. For centuries, scientists have used slides, counting chambers (hemocytometers), and diluting and staining solutions for this task. Then, automated hemocytometry began. This science, now linked to the daily routine of laboratory hematology, has completed an overwhelming path over a few decades. Our laboratories today operate with versatile multiparameter systems, ranging from complex single-channel instruments to bulky continuous flow machines. In terms of clinical information obtained from a simple routine blood test, the full exploitation of their potential depends on the operators' imagination and courage. A comprehensive review of the scientific publications that have accompanied the development of hemocytometry from the 1950s to today would require entire volumes. More than seven hundred contributions that authors worldwide have published in Clinical and Laboratory Haematology until 2007 and then the International Journal of Laboratory Hematology are summarized. Such journals have represented and hopefully will continue to represent the privileged place of welcome for future scientific research in hemocytometry. Improved technologies, attention to quality, new reagents and electronics, information technology, and scientist talent ensure a more profound and deeper knowledge of cell properties: current laboratory devices measure and count even minor immature or pathological cell subpopulations. Full-field hemocytometry includes the analysis of nonhematic fluids, digital adds to the microscope, and the development of effective point-of-care devices.

Prognostic Value of Nucleated RBCs for Patients With Suspected Sepsis in the Emergency Department: A Single-Center Prospective Cohort Study

Supplemental Digital Content is available in the text.

OBJECTIVES:

Increase of nucleated RBCs in peripheral blood has been shown to be predictive of mortality in ICU patients. The aim of this study was to explore the prognostic value of nucleated RBCs in the first blood sample taken at admission to the emergency department from patients with suspected sepsis.

DESIGN:

Single-center prospective cohort study.

SETTING:

Emergency department.

PATIENTS:

One-thousand two-hundred thirty-one consecutive adult patients with suspected sepsis were included in a prospective quality register-based cohort study. Inclusion criteria were as follows: patients received in rapid response team with blood cultures taken and immediate antibiotics given in the emergency department.

Intervention:

Not applicable.

MEASUREMENT AND MAIN RESULTS:

Nucleated RBCs, Sequential Organ Failure Assessment score, Quick Sequential Organ Failure Assessment, Charlson Comorbidity Index, and commonly used laboratory tests measured in the emergency department were compared with 30-day mortality. Nvaucleated RBC counts were divided into five groups, called “Nucleated RBC score,” according to nucleated RBC count levels and analyzed with logistic regression together with the Sequential Organ Failure Assessment score and Charlson Comorbidity Index. Of the 262 patients with nucleated RBCs equal to or higher than the detection limit (0.01 × 10⁹/L), 26% died within 30 days, compared with 12% of the 969 patients with nucleated RBCs below the detection limit (p < 0.0001). Mortality was significantly higher for each increase in Nucleated RBC score, except from score 2 to 3, and was 62% in the highest group. In multivariate logistic regression, odds ratios for 30-day mortality were as follows: Nucleated RBC score: 1.33 (95% CI, 1.13–1.56), Sequential Organ Failure Assessment score: 1.32 (1.29–1.56), and Charlson Comorbidity Index: 1.17 (1.09–1.25).

CONCLUSIONS:

Most patients with suspected sepsis in emergency department had undetectable nucleated RBCs at admission to the emergency department. However, increased nucleated RBCs significantly predicted 30-day mortality. Nucleated RBCs may provide additional prognostic information to Sequential Organ Failure Assessment score and other laboratory tests.

Improving the efficiency of the autoverification workflow for nucleated red blood cell reporting in the hematology laboratory

OBJECTIVE

Although the microscopic manual count is considered the standard method for NRBC enumeration, modern hematology analyzers can perform this task automatically with reliable accuracy and efficiency. This study aims to evaluate the diagnostic performance of the Sysmex XN hematology analyzer and to construct the optimal workflow for accurate and efficient NRBC reporting.

METHODS

Specimens containing different levels of NRBC were included. Analytical performance was evaluated via method comparison with flow cytometry (FCM) and manual count (MC). Clinical sensitivity was analyzed by ROC analysis using manual count as the standard method.

RESULTS

Correlation study of %NRBC with FCM and MC demonstrated an r value of 0.925 (95% CI 0.905 to 0.942) and 0.990 (95% CI 0.987 to 0.992) with a mean difference of -0.8 (95%CI: -6.7 to +5.0) and +0.50 (95% CI: -6.7 to +7.7), respectively. When the automated NRBC count was equal to zero and >0.07 × 10⁹ /L, the false-negative rate and false-positive rate were 100%, respectively; hence, manual slide review could be omitted. A false-positive rate of 72.7% was noted in specimens containing NRBC count less than 0.07 × 10⁹ /L.

CONCLUSION

The Sysmex XN can help improve the efficiency of NRBC enumeration owing to its accuracy, rapidity, and automation. However, further studies are required to improve the accuracy of detection in specimens containing a very low level of NRBC.

The VP1u of Human Parvovirus B19: A Multifunctional Capsid Protein with Biotechnological Applications

The viral protein 1 unique region (VP1u) of human parvovirus B19 (B19V) is a multifunctional capsid protein with essential roles in virus tropism, uptake, and subcellular trafficking. These functions reside on hidden protein domains, which become accessible upon interaction with cell membrane receptors. A receptor-binding domain (RBD) in VP1u is responsible for the specific targeting and uptake of the virus exclusively into cells of the erythroid lineage in the bone marrow. A phospholipase A₂ domain promotes the endosomal escape of the incoming virus. The VP1u is also the immunodominant region of the capsid as it is the target of neutralizing antibodies. For all these reasons, the VP1u has raised great interest in antiviral research and vaccinology. Besides the essential functions in B19V infection, the remarkable erythroid specificity of the VP1u makes it a unique erythroid cell surface biomarker. Moreover, the demonstrated capacity of the VP1u to deliver diverse cargo specifically to cells around the proerythroblast differentiation stage, including erythroleukemic cells, offers novel therapeutic opportunities for erythroid-specific drug delivery. In this review, we focus on the multifunctional role of the VP1u in B19V infection and explore its potential in diagnostics and erythroid-specific therapeutics.

Evaluation and comparison of the new Mindray BC-6200 hematology analyzer with ADVIA 2120i

BACKGROUND

The Mindray BC-6200 is a new automatic hematology analyzer that quantifies the parameters of blood morphology and leukocyte differential in five populations (5-Diff). The aim of the study was to evaluate the BC-6200 and compare it with the Siemens ADVIA 2120i analyzer.

MATERIALS AND METHODS

The comparison between BC-6200 and ADVIA 2120i analyzers was performed using 390 whole blood samples collected on K₃ EDTA. For the BC-6200, the carryover effect, precision, and linearity were evaluated. 138 samples were used to assess the sensitivity and flag ability, suggesting the presence of abnormal cells such as blasts, immature granulocytes, or atypical lymphocytes. Flagging results were compared with microscopic evaluation of blood smears.

RESULTS

The BC-6200 analyzer showed a high correlation (r ≥ .97) with ADVIA 2120i for most of the compared parameters except RDW (r = .8350), MPV (r = .7634), Mon# (r = .8366), Baso# (r = .9205), and NRBC (r = .3768). The BC-6200 had better correlation with microscopic evaluation for NRBC (r = .8902) compared with ADVIA 2120i (r = .5677). The BC-6200 has shown high efficiency for flagging blasts (80.4%), immature granulocytes (80.5%), and atypical lymphocytes (69.0%).

CONCLUSION

The new Mindray BC-6200 hematology analyzer provides high measurements precision and good correlation with ADVIA 2120i for most of the morphology and 5-diff parameters.

The Blood Circulating Rare Cell Population. What is it and What is it Good For?

Blood contains a diverse cell population of low concentration hematopoietic as well as non-hematopoietic cells. The majority of such rare cells may be bone marrow-derived progenitor and stem cells. This paucity of circulating rare cells, in particular in the peripheral circulation, has led many to believe that bone marrow as well as other organ-related cell egress into the circulation is a response to pathological conditions. Little is known about this, though an increasing body of literature can be found suggesting commonness of certain rare cell types in the peripheral blood under physiological conditions. Thus, the isolation and detection of circulating rare cells appears to be merely a technological problem. Knowledge about rare cell types that may circulate the blood stream will help to advance the field of cell-based liquid biopsy by supporting inter-platform comparability, making use of biological correct cutoffs and “mining” new biomarkers and combinations thereof in clinical diagnosis and therapy. Therefore, this review intends to lay ground for a comprehensive analysis of the peripheral blood rare cell population given the necessity to target a broader range of cell types for improved biomarker performance in cell-based liquid biopsy.

Cutoff Value for Correcting White Blood Cell Count for Nucleated Red Blood Cells: What is it? Why is it Important?

Nucleated red blood cells (RBCs) are normally observed in the peripheral blood of neonates and during pregnancy. Under other conditions, the presence of nucleated RBCs in circulating blood indicates disorder in the blood-producing mechanism. The increased presence of nucleated RBCs, however, falsely elevates the leukocyte count, as measured by most automated hematology analyzers, warranting a manual correction of the leukocyte count. For a long time, cutoff values for correcting white blood cell (WBC) count for the presence of nucleated RBCs have been used regularly, particularly in developing countries. However, because those values are largely subjective, they can vary widely between laboratories worldwide. These varied cutoff values include 1, 5, 10, 20, and 50; it appears that the numbers 5 and 10 are the most common values used in corrections; the reasons require further elucidation. In this article, we discuss the merits of correcting the WBC count for nucleated RBCs at certain cutoff points.

Automated nucleated red blood cell count using the Mindray BC-6800 hematology analyzer

INTRODUCTION

In current laboratory practice, obtaining a nucleated red blood cell (NRBC) count by manual microscopy (MM) is a laborious and time-consuming process. Modern hematology analyzers based on different technologies and methods have variable accuracies when determining NRBC counts. The aim of this study was to compare NRBC counts acquired by an automated Mindray BC-6800 analyzer (BC-6800), a flow cytometry (FC) reference method, and traditional MM.

METHODS

A hundred EDTA samples with initial NRBC flags from the BC-6800 were included. FC was used as a reference method to correlate the NRBC count with BC-6800 and MM counts. In addition, the performance of the Mindray SC-120 analyzer for preparing automated blood films for manual NRBC counting was compared to that of manually prepared blood films.

RESULTS

The NRBC counts obtained with the BC-6800 and MM vs the reference method were highly correlated (r = .994 and .989, respectively). However, the BC-6800 showed a lower bias than MM when compared with FC (0.3 × 10⁹ /L and -6.0 × 10⁹ /L, respectively). NRBC counts obtained using the automated Mindray SC-120 films were comparable to manually prepared films.

CONCLUSION

The Mindray CAL8000 automated hematology system, which is composed of the BC-6800 and the SC-120, yields a precise NRBC count and can replace the traditional MM method for obtaining accurate and reproducible NRBC counts in high-value samples, such as patient monitoring samples used to determine the necessity of transfusion therapy in thalassemia patients. Moreover, this method offers several advantages, including a faster turnaround time, labor savings, and cost effectiveness.