Reference intervals of cell population data parameters in Sysmex XN-Series and its patterns of changes from early adulthood to geriatric ages in South Korea

INTRODUCTION

Cell population data (CPD) parameters may be putative biomarkers for the screening of various diseases including some infections and myelodysplastic syndrome. This study aimed to establish the age- and sex-specific reference intervals (RIs) for the CPD parameters in the Korean population.

METHODS

The reference population for the RIs of CPD parameters comprised 124 856 subjects aged 20-99 years. CPD parameters were obtained from Sysmex XN-2000 (Kobe, Japan) datasets from 17 health promotion centers in 13 South Korean cities. We determined significant partitions for age and sex, and calculated RIs according to Clinical and Laboratory Standards Institute C28-A3 guidelines.

RESULTS

The side scattered light intensity in the neutrophil area and the lymphocyte area did not require sex-related partitioning except in those over the age of 50, among whom the lower limit (LL) and upper limit (UL) were lower in females. However, the side scattered light distribution width in the lymphocyte area required age- and sex-related partitioning, in which LL and UL were higher in females. The LL and UL of the fluorescent light distribution width were higher in males in the neutrophil area and higher in females in the lymphocyte area, but age-related partitioning was not required. The forward scattered light intensity in the neutrophil area, lymphocyte area, and monocyte area did not require age-related partitioning in males.

CONCLUSION

This study has determined comprehensive age- and sex-specific RIs for CPD parameters, which could help to prove the clinical significance of these parameters in the Sysmex XN-2000.

Parameters of the complete blood count predict in hospital mortality

INTRODUCTION

Mortality rates are used to evaluate the quality of hospital care after adjusting for disease severity and, commonly also, for age, comorbidity, and laboratory data with only few parameters of the complete blood count (CBC).

OBJECTIVE

To identify the parameters of the CBC that predict independently in-hospital mortality of acutely admitted patients.

POPULATION

All patients were admitted to internal medicine, cardiology, and intensive care departments at the Laniado Hospital in Israel in 2018 and 2019.

VARIABLES

Independent variables were patients' age, sex, and parameters of the CBC. The outcome variable was in-hospital mortality.

ANALYSIS

Logistic regression. In 2018, we identified the variables that were associated with in-hospital mortality and validated this association in the 2019 cohort.

RESULTS

In the validation cohort, a model consisting of nine parameters that are commonly available in modern analyzers had a c-statistics (area under the receiver operator curve) of 0.86 and a 10%-90% risk gradient of 0%-21.4%. After including the proportions of large unstained cells, hypochromic, and macrocytic red cells, the c-statistic increased to 0.89, and the risk gradient to 0.1%-29.5%.

CONCLUSION

The commonly available parameters of the CBC predict in-hospital mortality. Addition of the proportions of hypochromic red cells, macrocytic red cells, and large unstained cells may improve the predictive value of the CBC.

Comparison between blood hemoglobin concentration determined by point-of-care device and complete blood count in adult patients with dengue

Background

Hematocrit measurement has been an indispensable tool for monitoring plasma leakage and bleeding in dengue patients. However, hematocrit measurement by automated methods is hampered by frequent venipunctures. Utility of point-of-care hemoglobin (POC-Hb) test for monitoring dengue patients has not been established. We evaluated the relationship between hemoglobin measured by POC-Hb testing and hematocrit measured by the automated method in adult dengue patients.

Methodology and principal findings

Adult dengue patients were recruited at two university hospitals in Thailand from October 2019 to December 2020. POC-Hb test was performed using capillary blood simultaneously with venipuncture to obtain whole blood for an automated complete blood count (CBC) analysis. The correlation of hemoglobin and hematocrit measurement was evaluated. A total of 44 dengue patients were enrolled. Twenty-nine patients (65.9%) were female, with a median age of 31 years (interquartile range 22–41). Of the enrolled patients, 30 (68.2%), 11 (25.0%), and 3 (6.8%) were classified as dengue without warning signs, with warning signs, and severe dengue, respectively. Seven patients (15.9%) had hemoconcentration, and five patients (11.3%) had bleeding. A total of 216 pairs of POC-Hb and CBC were evaluated. A significant positive correlation was observed between hemoglobin measured by POC-Hb testing and hematocrit measured by an automated CBC (r = 0.869, p <0.001). Bland-Altman analysis between hemoglobin measured by POC-Hb testing and an automated CBC showed a bias of -0.43 (95% limit of agreement of -1.81 and 0.95). Using the cutoff of POC-Hb ≥20% as a criteria for hemoconcentration, the sensitivity and specificity of hemoconcentration detected by POC-Hb device were 71.4% and 100.0%, respectively.

Conclusions

Hemoglobin measurement by POC-Hb testing has a strong correlation with hematocrit in adult patients with dengue fever. However, the sensitivity in detecting hemoconcentration is fair. The adjunct use of capillary POC-Hb testing can decrease the frequency of venipuncture. Further study in children is encouraged.

The natural history of dengue has the unique characteristic of plasma leakage that results in hemoconcentration as well as vasculopathy and thrombocytopenia that result in bleeding. Therefore, hematocrit monitoring is a crucial tool to guide management in dengue patients. Microhematocrit adjunct with a complete blood count (CBC) to monitor dengue patients were traditionally performed to decrease the frequency of venipuncture. However, microhematocrit is currently less preferred to the point-of-care hemoglobin monitoring tools to measure red cells in other diseases. There has been no study investigating the feasibility of using point-of-care hemoglobin (POC-Hb) to monitor dengue patients. We studied the correlation of hemoglobin measured by POC-Hb testing and hematocrit measured by an automated CBC in adult dengue patients. We were able to show a strong positive correlation between the two measurements (r = 0.869, p <0.001). Using the rise of POC-Hb value of ≥20% above the convalescent value as the criteria for detecting hemoconcentration by POC-Hb testing, measurement of hemoglobin using POC-Hb has a sensitivity of 71.4% for detecting hemoconcentration compared to the traditional hematocrit criteria. Our findings support the use of POC-Hb testing adjunct with a complete blood count to guide fluid management in dengue patients.

Interferents of Automated Reticulocyte Analysis Integrated with Relevant Clinical Cases

BACKGROUND

Reticulocyte count (RET) has been used for many years to estimate the erythropoietic activity of the bone marrow. Fully automated methods not only provide enhanced precision and accuracy, but also enable reliable measurements of mRNA content and cellular indices. However, problems still exist, such as interference. The aim of the present study was to investigate the interferents of Sysmex XN 9000 reticulocyte analysis and ensure the accuracy of the results.

METHODS

We collected a total of 510 specimens from normal control patients and patients with various diseases including anemias, leukemias, infectious diseases, immune diseases, kidney disease, etc. Correlation of the agreement for reticulocytes between the new methylene blue (NMB) visual microscopy method and automated reticulocyte counting was evaluated by paired sample method according to the CLSI-ICSH document H44-A2-Methods for Reticulocyte Count. Blood smear microscopic examination was carried out on the disturbed samples, and the interferents were analyzed with the medical history, flagging algorithms, the warning information, and the microscopic examination.

RESULTS

A total of 44 (8.6%) cases exhibited interference. The main interferents of spuriously high reticulocyte count were caused by parasites, such as malaria, as well as suspicious autofluorescence due to drugs, while the main interferents of spuriously low reticulocyte count were caused by RBC fragments.

CONCLUSIONS

Detection of potential interferences may be accomplished through alarm information and flagging algorithms incorporated into the instrument and by examination of a blood film to ensure absence of relevant interferences.

Heinz body-related interference with leukocyte and erythrocyte variables obtained by an automated hematology analyzer in cats

Heinz bodies (HBs) are known to interfere with automated hematology in cats, particularly with the white blood cell (WBC) count. We evaluated the influence of feline HBs on the complete blood count (CBC) results obtained using a flow cytometry-based analyzer. We retrospectively selected cats with circulating HBs and reviewed the results of their CBCs, including red blood cell (RBC) indices, basophil/lobularity (Baso) WBC count (WBCB), peroxidase (Perox) WBC count (WBCP), and cytograms. Based on the presence or absence of HB-related artifacts in their Baso cytogram, cats were grouped into Baso-HBs and HBs groups, respectively, for comparison. The WBCB and WBCP were compared to manual counts of WBCs carried out on blood smears at 400× (MC-WBC). We included 32 cats in our study: 9 of 32 were in the Baso-HBs group, and 23 of 32 were in the HBs group. Baso-HBs cats had a significantly increased HB percentage (p < 0.001), WBCB (p < 0.001), difference between WBCB and WBCP (p < 0.001), lymphocyte count (p < 0.001), mean corpuscular hemoglobin concentration (p < 0.001), and difference between calculated and measured erythrocyte hemoglobin concentrations (p < 0.001) compared to HBs cats. In Baso-HBs cats, the WBCB was significantly higher than the WBCP (p = 0.02); no significant difference was detected between the WBCP and the MC-WBC (p = 0.88). Evaluation of automated CBC results raised the suspicion of HB-related interference when using a hematology analyzer in cats; hence, blood smear examination remains essential in routine practice.

Performance Evaluation of the Mindray BC 6800 Hematology Analyzer and Flag Comparison with the XE-2100 and Manual Microscopy

BACKGROUND

The Mindray BC-6800 automated hematology analyzer is an automated hematology analyzer and 5-part leukocyte differential counter for in vitro diagnostic use in clinical laboratories. It is necessary to undergo an evaluation before the instrument is used to test patient samples.

METHODS

The performance was evaluated with regards to precision, linearity, carry-over, and method comparison. The flag performances were evaluated and compared with the Sysmex XE-2100 hematology analyzer and manual microscope in the hematology laboratory of a tertiary hospital in China.

RESULTS

There was minimal carryover (< 0.05%) and excellent linearity for white blood cells and platelet (PLT) counts (r > 0.999). The BC-6800 displayed very good correlation (r > 0.97) with the XE-2100 for blood cell count and cell differential parameters. In a comparison of 295 leukocyte differential count results analyzed in parallel with manual microscopy, the main flags (immature granulocytes, blasts, abnormal lymphocytes) showed approxi-mately the same sensitivity and specificity on both analyzers (sensitivity > 90%, specificity > 78%).

CONCLUSIONS

The BC-6800 showed excellent performance and supplied confidence in flag information for abnormal samples in the routine hematology laboratory.

Performance Evaluation of a New Generation of Automated Analyzer for Pleural and Peritoneal Fluids Cytology

BACKGROUND

Hematologic counters with dedicated body fluids mode allows these samples to be analyzed in an automated manner. Our aim was to evaluate the performance of the Sysmex XN-3000 and compare it with the Sysmex XE-5000, in use in our laboratory for cytological analysis of body fluids.

METHODS

We studied 108 pleural and peritoneal fluids. Laboratory routine included manual and automated cell counts. The Sysmex XN-3000 validation protocol included precision, carryover, linearity studies, and comparison with traditional microscopic differential counts and with the analyzer in use.

RESULTS

Sysmex XN-3000 met all the criteria for analytical quality with strong correlation with microscopy (r = 0.95 for MN and PMN) and agreement of 93% (kappa = 0.813, p < 0.0001). Comparison between both analyzers revealed no significant differences and strong correlation regarding WBC and RBC (r > 0.98), mononuclear and polymorphonuclear cells (r = 0.99).

CONCLUSIONS

Sysmex XN-3000 showed strong correlation and agreement with traditional microscopy with an equivalent performance compared to the XE-5000.

Complete blood count reference intervals from a healthy adult urban population in Kenya

BACKGROUND

There are racial, ethnic and geographical differences in complete blood count (CBC) reference intervals (RIs) and therefore it is necessary to establish RIs that are population specific. Several studies have been carried out in Africa to derive CBC RIs but many were not conducted with the rigor recommended for RI studies hence limiting the adoption and generalizability of the results.

METHOD

By use of a Beckman Coulter ACT 5 DIFF CP analyser, we measured CBC parameters in samples collected from 528 healthy black African volunteers in a largely urban population. The latent abnormal values exclusion (LAVE) method was used for secondary exclusion of individuals who may have had sub-clinical diseases. The RIs were derived by both parametric and non-parametric methods with and without LAVE for comparative purposes.

RESULTS

Haemoglobin (Hb) levels were lower while platelet counts were higher in females across the 4 age stratifications. The lower limits for Hb and red blood cell parameters significantly increased after applying the LAVE method which eliminated individuals with latent anemia and inflammation. We adopted RIs by parametric method because 90% confidence intervals of the RI limits were invariably narrower than those by the non-parametric method. The male and female RIs for Hb after applying the LAVE method were 14.5-18.7 g/dL and 12.0-16.5 g/dL respectively while the platelet count RIs were 133-356 and 152-443 x10(3) per μL respectively.

CONCLUSION

Consistent with other studies from Sub-Saharan Africa, Hb and neutrophil counts were lower than Caucasian values. Our finding of higher Hb and lower eosinophil counts compared to other studies conducted in rural Kenya most likely reflects the strict recruitment criteria and healthier reference population after secondary exclusion of individuals with possible sub-clinical diseases.

Fragmentation of Red Blood Cells Caused Pseudothrombocytosis in a Patient

BACKGROUND

Pseudothrombocytopenia, caused by platelet (PLT) clumping, is often found in clinical studies [1]. However, pseudothrombocytosis resulting from the fragmentation of red blood cells (RBCs) is a very rare phenomenon.

METHODS

EDTA-K2 anticoagulation was used on a sample of venous blood extracted from the patient. A Symex XN9000 automatic blood analyzer was used to conduct CBC + DIFF mode and CBC + DIFF + RET mode tests, stained smear microscopy.

RESULTS

The Symex XN9000 automatic blood analyzer was used to conduct CBC + DIFF mode test; PLTs were measured at 570 x 109/L. Stained smear microscopy revealed the number of PLTs did not conform to the instrument measured 570 x 109/L. "RET" alarm instrument, switch to CBC + DIFF + RET mode for testing. The second test result showed PLTs at 128 x 109/L, which accords with artificial microscopy.

CONCLUSIONS

This was a case of a very rare phenomenon: the fragmentation of RBCs caused pseudothrombocytosis.

A Microfluidic Cytometer for Complete Blood Count With a 3.2-Megapixel, 1.1- μm-Pitch Super-Resolution Image Sensor in 65-nm BSI CMOS

Based on a 3.2-Megapixel 1.1- μm-pitch super-resolution (SR) CMOS image sensor in a 65-nm backside-illumination process, a lens-free microfluidic cytometer for complete blood count (CBC) is demonstrated in this paper. Backside-illumination improves resolution and contrast at the device level with elimination of surface treatment when integrated with microfluidic channels. A single-frame machine-learning-based SR processing is further realized at system level for resolution correction with minimum hardware resources. The demonstrated microfluidic cytometer can detect the platelet cells (< 2 μm) required in CBC, hence is promising for point-of-care diagnostics.

Enhancement of Capture Sensitivity for Circulating Tumor Cells in a Breast Cancer Patient's Blood by Silicon Nanowire Platform

The separation of circulating tumor cells (CTCs) from the blood of cancer patients with high sensitivity is an essential technique for selecting chemotherapeutic agents at a patient-by-patient level. Recently, various research groups have reported a nanostructure-based platform for rare cell capture due to its high surface area and 3D nanotopographic features. However, evaluation of capture sensitivity based on chemical modification of the nanostructure surface has not yet been performed. Here, we evaluated the capture sensitivity for CTCs from the blood of three patients diagnosed with stage IV metastatic breast cancer by using the following three platforms: streptavidin-conjugated silicon nanowire (STR-SiNW), poly-l-lysine-coated silicon nanowire (PLL-SiNW), and poly-l-lysine-coated glass (PLL-glass). The number of evaluated CTCs on STR-SiNW, PLL-SiNW, and PLL-glass were 16.2 ± 5.5 cells, 7.3 ± 2.9 cells, and 4.7 ± 1.5 cells, respectively, per 0.5 ml. Therefore, we suggest that the STR-SiNW platform is highly adaptable for the quantitative evaluation of CTCs from the blood of cancer patients in the clinical setting.

Label-free whole blood cell differentiation based on multiple frequency AC impedance and light scattering analysis in a micro flow cytometer

We developed a microfluidic sensor for label-free flow cytometric cell differentiation by combined multiple AC electrical impedance and light scattering analysis. The measured signals are correlated to cell volume, membrane capacity and optical properties of single cells. For an improved signal to noise ratio, the microfluidic sensor incorporates two electrode pairs for differential impedance detection. One-dimensional sheath flow focusing was implemented, which allows single particle analysis at kHz count rates. Various monodisperse particles and differentiation of leukocytes in haemolysed samples served to benchmark the microdevice applying combined AC impedance and side scatter analyses. In what follows, we demonstrate that AC impedance measurements at selected frequencies allow label-free discrimination of platelets, erythrocytes, monocytes, granulocytes and lymphocytes in whole blood samples involving dilution only. Immunofluorescence staining was applied to validate the results of the label-free cell analysis. Reliable differentiation and enumeration of cells in whole blood by AC impedance detection have the potential to support medical diagnosis for patients with haemolysis resistant erythrocytes or abnormally sensitive leucocytes, i.e. for patients suffering from anaemia or leukaemia.

[The Technical Innovation of Medical Engineering and Application Development in POCT Devices.]

Medical doctors have been utilizing POCT devices at POC sites (ER, ICU, and operation rooms). Now, POCT devices are used by health care professionals in the physician's office and also for home healthcare. Home healthcare (welfare/nursing care) is a focus area of the MHLW initiative to develop healthcare in order to resolve the "2025 problem". The role of POCT is important in resolving this issue.

Performance of computer vision in vivo flow cytometry with low fluorescence contrast

Detection and enumeration of circulating cells in the bloodstream of small animals are important in many areas of preclinical biomedical research, including cancer metastasis, immunology, and reproductive medicine. Optical in vivo flow cytometry (IVFC) represents a class of technologies that allow noninvasive and continuous enumeration of circulating cells without drawing blood samples. We recently developed a technique termed computer vision in vivo flow cytometry (CV-IVFC) that uses a high-sensitivity fluorescence camera and an automated computer vision algorithm to interrogate relatively large circulating blood volumes in the ear of a mouse. We detected circulating cells at concentrations as low as 20 cells/mL. In the present work, we characterized the performance of CV-IVFC with low-contrast imaging conditions with (1) weak cell fluorescent labeling using cell-simulating fluorescent microspheres with varying brightness and (2) high background tissue autofluorescence by varying autofluorescence properties of optical phantoms. Our analysis indicates that CV-IVFC can robustly track and enumerate circulating cells with at least 50% sensitivity even in conditions with two orders of magnitude degraded contrast than our previous in vivo work. These results support the significant potential utility of CV-IVFC in a wide range of in vivo biological models.

Single-step preparation and image-based counting of minute volumes of human blood

Current flow-based blood counting devices require significant medical infrastructure and are not appropriate for field use. In this article we report on the development of a sample preparation, measurement, and analysis method that permits automated and accurate counting of red blood cells (RBCs), white blood cells (WBCs), and platelets, as well as allowing a 3-part differential of the WBCs to be performed on extremely small volumes of whole blood. This method is compatible with portable instrumentation that can be deployed in the field. The method consists of serially diluting blood samples first with sodium dodecyl sulfate dissolved in phosphate buffered saline, then in acridine orange dissolved in phosphate buffered saline, followed by fluorescence and dark field imaging with low magnification objectives. Image analysis is performed to extract cell counts and differentials. We performed a paired analysis of 20 volunteers with complete blood count values both within and beyond the normal reference range using a commercial automated hematology analyzer and the image-based method, with the new method achieving accuracies comparable to that of the commercial system. Because the sample preparation and imaging are simple and inexpensive to implement, this method has applications for pediatrics, clinician offices, and global health in regions that do not have access to central hematology laboratories.

Development of simple equations for effective screening of spurious hemolysis in whole-blood specimens

INTRODUCTION

We aimed to identify simple but reliable indices for effective screening of spurious hemolysis in whole-blood specimens.

METHODS

Thirteen inpatient whole-blood samples were divided in two aliquots. The former was left untreated, whereas the latter was mechanically hemolyzed by forced aspiration with an insulin syringe. All aliquots were tested on Siemens Advia 2120 and Sysmex XE-2100. The hemolysis index (HI) was also assessed in centrifuged plasma.

RESULTS

The mechanical hemolysis generated a 4-40% decrease in red blood cells (RBCs). A statistically significant decrease was observed for hematocrit (Ht) and mean corpuscular volume (MCV), whereas mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and platelet count were increased. The values of hemoglobin (Hb) and white blood cells remained substantially unchanged. Two specific equations ([Ht/Hb] × √MCV and [Ht/Hb] × 100) were developed. Both equations displayed an area under the curve of ≥0.99 for identifying spurious hemolysis, much greater than that of both RBC ghosts and immature platelet fraction. A highly significant correlation was also observed between results of these equations and percentage reduction in RBCs or HI increase.

CONCLUSION

Provided that these results will be confirmed in further studies, these equations may provide a reliable means for screening spurious hemolysis in whole-blood samples.

Cost-effective and rapid blood analysis on a cell-phone

We demonstrate a compact and cost-effective imaging cytometry platform installed on a cell-phone for the measurement of the density of red and white blood cells as well as hemoglobin concentration in human blood samples. Fluorescent and bright-field images of blood samples are captured using separate optical attachments to the cell-phone and are rapidly processed through a custom-developed smart application running on the phone for counting of blood cells and determining hemoglobin density. We evaluated the performance of this cell-phone based blood analysis platform using anonymous human blood samples and achieved comparable results to a standard bench-top hematology analyser. Test results can either be stored on the cell-phone memory or be transmitted to a central server, providing remote diagnosis opportunities even in field settings.

Numerical simulation of particle dynamics in an orifice-electrode system. Application to counting and sizing by impedance measurement

This paper describes how to numerically tackle the problem of counting and sizing particles by impedance measurement in an orifice-electrode system. The model allows to simulate the particle dynamics submitted to strong hydrodynamic stresses through a microorifice and to compute the voltage pulses generated by the modification of the inner dielectric medium. This approach gives important information about particles size distribution and allows to quantify the role of trajectory and orientation of particles on the size measurement.

Fast multi-spectral imaging technique for detection of circulating endothelial cells in human blood samples

The appearance of non-blood cells circulating in human peripheral bloodstream indicates an abnormal condition. One important category of these cells is circulating endothelial cells (CECs) shed by compromised blood vessels. Clinical applications that measure the blood level of CECs are hindered due to a lack of standardized instruments. The major challenge in detecting circulating non-blood cells is their extreme scarcity; 1 in 106 to 107. Described here is a new method for detection of rare cells in blood samples deposited on the adhesive microscopic slides and immunostained with distinct fluorescent markers. The key novelty of the proposed approach is an intelligent search principle and a dual-mode scanner to implement this principle. To begin, a fast scanning that uses a single beam is performed in the spectral channel where only rare cells produce florescence. Once a target cell is registered, the scanner switches on the imaging mode, auto-focuses and then records images in multiple spectral channels at the selected area. The instrument runs in repetitive cycles until the entire slide is scanned. The technology has been validated via detection of human umbilical vein endothelial cells spiked into human blood samples. In addition, the operational principle can be adapted for detection of other types of rare cells in blood.

A quartz nanopillar hemocytometer for high-yield separation and counting of CD4(+) T lymphocytes

We report the development of a novel quartz nanopillar (QNP) array cell separation system capable of selectively capturing and isolating a single cell population including primary CD4(+) T lymphocytes from the whole pool of splenocytes. Integrated with a photolithographically patterned hemocytometer structure, the streptavidin (STR)-functionalized-QNP (STR-QNP) arrays allow for direct quantitation of captured cells using high content imaging. This technology exhibits an excellent separation yield (efficiency) of ~95.3 ± 1.1% for the CD4(+) T lymphocytes from the mouse splenocyte suspensions and good linear response for quantitating captured CD4(+) T-lymphoblasts, which is comparable to flow cytometry and outperforms any non-nanostructured surface capture techniques, i.e. cell panning. This nanopillar hemocytometer represents a simple, yet efficient cell capture and counting technology and may find immediate applications for diagnosis and immune monitoring in the point-of-care setting.

ENU-based phenotype-driven screening

Deciphering the contribution of individual genes and in turn pathways to cellular processes can be complicated and is often based on prior knowledge or assumptions of gene function. Phenotype-driven mutagenesis screens based around n-ethyl-n-nitrosurea (ENU) have been successful in a wide range of physiological systems in identifying novel genes that contribute to a given phenotype. Here, we describe methodologies we have employed in analysing cellular phenotypes in pipelines of mutagenised mice. Examples of primary screens to identify outliers, and secondary screens to provide a more detailed characterisation are outlined.

Comparison of platelet clumping and complete blood count results with Sysmex XT-2000iV in feline blood sampled on EDTA or EDTA plus CTAD (citrate, theophylline, adenosine and dipyridamole)

False thrombocytopenia may result from platelet aggregation, especially in feline ethylenediamine tetra-acetic acid (EDTA) blood specimens. Citrate, theophylline, adenosine and dipyridamole (CTAD) was added to 46 feline EDTA specimens to test its anti-aggregation action. Platelet aggregation was estimated from blood films and a complete blood count was performed with a Sysmex XT-2000iV analyser. Platelet aggregation score was >2 in 11/46 EDTA tubes and only in one EDTA+CTAD specimen. The platelet count was higher in all CTAD-supplemented tubes except one, medians measured by cytometry being 225.5 × 10(9)/l and 249.0 × 10(9)/l in EDTA and EDTA+CTAD, respectively (P = 0.007). Adding CTAD had statistically and analytically significant but moderate effects on other blood variables, the most intense variations being observed for reticulocytes (about 3% higher in EDTA specimens) and reticulocyte indexes. Addition of CTAD to EDTA when sampling feline blood is a useful option to reduce platelet clumping.

Automatic cytometric device using multiple wavelength excitations

Precise identification of eosinophils, basophils, and specific subpopulations of blood cells (B lymphocytes) in an unconventional automatic hematology analyzer is demonstrated. Our specific apparatus mixes two excitation radiations by means of an acousto-optics tunable filter to properly control fluorescence emission of phycoerythrin cyanin 5 (PC5) conjugated to antibodies (anti-CD20 or anti-CRTH2) and Thiazole Orange. This way our analyzer combining techniques of hematology analysis and flow cytometry based on multiple fluorescence detection, drastically improves the signal to noise ratio and decreases the spectral overlaps impact coming from multiple fluorescence emissions.

Evaluation of the Sysmex pocH-1001 haematology analyser in an outdoor oncology service

Since rapid blood count analysis as near patient testing is expanding, we evaluated the use of a Sysmex pocH-100i compact haematology analyser in an outdoor oncology setting according to the recently published International Council for Standardization in Haematology (ICSH) guidelines. In total, 838 blood samples from oncology patients were analysed by pocH-100i and re-analysed by a high-throughput haematology analyser for comparison (Abbott CD-4000 or Sysmex XE-2100) to evaluate in use imprecision, comparability and vote-outs. Imprecision was less than 5%, except for platelet enumeration in the low range (within-run imprecision 7%). Good comparability was found even for platelet enumeration in the low range (r2 = 0.82). Vote-outs were found in 10.6% of examined samples. In conclusion, the Sysmex pocH-100i demonstrates good imprecision conform with former publications, produces reliable results in normal and in lower ranges comparable to the results of high throughput haematology analysers. In a well controlled management plan the Sysmex pocH-100i is suitable for near patient testing in oncology.

[Utility of microsemi LC-667CRP in point of care testing system for acute inflammatory disease]

We examined the basic performance of "Microsemi LC-667CRP" (LC-667, HORIBA, Ltd.) which has been newly developed as compact laboratory instrument capable of simultaneous measuring of complete blood count (CBC) including 3-part differentials of white blood cells (WBC) and C-reactive protein (CRP) using whole blood anticoagulated with ethylenediaminetetraacetic acid (EDTA). We found that CBC and CRP were intra-assay-reproducible (n = 10, CVs < 5.0%). They also showed the good linearity and no definite carry-over. Concerning the WBC differentials, percentage of monocytes (MON%) showed less intra-assay reproducibility compared with those of granulocytes (GRA%) and lymphocytes (LYM%). We also evaluated the correlation of values obtained by LC-667 and routinely used instruments in our institute. Concerning the CBC and WBC differentials, excellent correlations were found between LC-667CRP and XE-2100 (SYSMEX CORPORATION) except MON%. In addition, whole blood CRP as well as plasma and serum CRP measured by LC-667 also showed the good correlations with serum CRP measured by 7600 (Hitachi High Technologies Corporation). From these findings, LC-667 was revealed to produce the clinically reliable data using only 18 microL of sample volume in 4 minutes. Point of care testing (POCT) has been developed as the laboratory system performed at or near the site of patient to reduce the turn around time. Therefore, LC-667 seemed useful in POCT for the patients with acute inflammatory disease especially in pediatrics.

[Establishment and evaluation of review criteria for ADVIA 120/2120 and different series of hematology analyzers]

OBJECTIVE

To establish the suitable review criteria for ADVIA 120/2120 and those for different series of hematology analyzers.

METHODS

A total of 2400 samples, including 6 blood neoplasms, were detected with ADVIA 120/2120 hematology analyzer, in which 1200 samples were detected by Sysmex XE-2100 and Beckman-Coulter LH750 hematology analyzers. In the meantime, blood smears were reviewed, and the results were analyzed statistically. The new review criteria were established by consulting and modifying the one as recommended by an international consensus group. Finally 300 samples were selected to validate the new review criteria.

RESULTS

The results of 2400 samples detected by ADVIA 120/2120 hematology analyzer were analyzed statistically according to the international consensus review rules and blood smear positive criteria formulated by Chinese experts. The true positive rate was 22.1% (n = 530), false positive rate 28.1% (n = 675), true negative rate 44.3% (n = 1063), false negative rate 5.5% (n = 132), and the smear review rate 50.2% (n = 1205). The false negative rate was over the acceptable limit of 5%. The new review criteria were established by amending the blood smear positive criteria, i. e. increasing the percentage of band neutrophils, eosinophils, basophils and monocytes and adjusting the international consensus review rules. Then the results were re-analyzed. The true positive rate, false positive rate, true negative rate and false negative rate were 15.5% (n = 371), 18.7% (n = 449), 61.6% (n = 1479) and 4.2% (n = 101) respectively. The smear review rate was 34.2% (n = 821) and no specimen of blood neoplasms was missed. On that basis, the current review criteria for ADVIA 120/2120, XE-2100 and LH750 hematology analyzer were proposed by adding some specific parameters. The results of 1200 samples with three instruments were analyzed according to the current criteria. And the false negative rates were 4.3%, 4.6% and 4.6%, and false positive rate 14.7%, 17.5% and 12.7% respectively. And no specimen of blood neoplasm was missed. The false negative rates of three instruments were 3.8%, 4.3% and 4.0% in validation teses.

CONCLUSION

The review criteria for three different series of hematology analyzers have been formulated for large general hospitals.

High-throughput lens-free blood analysis on a chip

We present a detailed investigation of the performance of lens-free holographic microscopy toward high-throughput on-chip blood analysis. Using a spatially incoherent source that is emanating from a large aperture, automated counting of red blood cells with minimal sample preparation steps at densities reaching up to approximately 0.4 x 10(6) cells/muL is presented. Using the same lens-free holographic microscopy platform, we also characterize the volume of the red blood cells at the single-cell level through recovery of the optical phase information of each cell. We further demonstrate the measurement of the hemoglobin concentration of whole blood samples as well as automated counting of white blood cells, also yielding spatial resolution at the subcellular level sufficient to differentiate granulocytes, monocytes, and lymphocytes from each other. These results uncover the prospects of lens-free holographic on-chip imaging to provide a useful tool for global health problems, especially by facilitating whole blood analysis in resource-poor environments.

Serial correlation of quality control data–on the use of proper control charts

BACKGROUND

Biochemical quality control (QC) data have been reported to be autocorrelated. Serial correlation may increase the rate of false alarms if the traditional exponentially weighted moving average (EWMA) control chart to monitoring the process mean is used. False alarms are the focus of this paper, where an alarm is defined as the occurrence of a QC value outside the three standard deviation control limits.

METHODS

Daily QC measurements of common biochemical (Vitros 500) and hematological (SF-3000 and Behring Coagulation Timer (BCT)) quantities were recorded during several months while methods and analyzers showed no signs of malfunctioning. The time series were examined for autocorrelation and the performance of the EWMAST chart was compared with that of the EWMA chart when autocorrelation was present.

RESULTS

Many of the time series showed significant signs of autocorrelation. Using the EWMA chart to monitor the process mean, false alarms were noted for positively autocorrelated time series, while this was seldom the case when the EWMAST chart was used. For some quantities, the EWMAST chart gave alarms. However, when the process autocorrelation and therefore the limits of the control chart were updated, the alarms given by the EWMAST chart were reduced or disappeared. In some cases the mean level changed over time, which is expected due to calibrations. This problem will be the topic of a subsequent paper.

CONCLUSIONS

Positive autocorrelation may be present in QC data. In this case the EWMAST chart should be used in place of the EWMA chart.

Use of hematopoietic progenitor cell count on the Sysmex XE-2100 for peripheral blood stem cell harvest monitoring

Successful peripheral blood stem cell (PBSC) collection depends on the timing of apheresis based on CD34+ cell enumeration. Because this analysis is expensive and induces organization difficulties, we evaluated hematopoietic progenitor cell (HPC) quantification on the Sysmex XE-2100 as a surrogate analysis. We tested 157 blood samples for CD34+ cells and HPC counts. We found a good linear correlation between HPC and CD34+ and determined simple rules allowing to use HPC count in daily practice. We set a positive cut-off >30 HPC/mm(3) for allowing PBSC harvest and a negative cut-off at 0 HPC/mm(3) for which collection should be delayed. These two situations accounted for 62% of cases and CD34+ cell count by flow cytometry confirmed HPC result in 95% of cases. Between 0 and 30 HPC/mm3, CD34+ enumeration is required for decision-making. We conclude that HPC count may be a useful surrogate for CD34+ enumeration in PBSC harvest monitoring.

Standardization and harmonization of the blood count: the role of International Committee for Standardization in Haematology (ICSH)

Scientific principles of standardization were first applied in haematology in 1963 when the International Committee for Standardization in Haematology was established with a primary objective to improve the measurement of haemoglobin. Subsequently, ICSH has established Expert Panels on a wide range of haematological topics, including especially a Panel on Cytometry. The purpose of haematological standardization is to obtain precision, accuracy, specificity and harmonization of results between different laboratories in all countries and also between different instruments or methods in the same laboratory. To achieve these objectives ICSH sponsors collaborative studies by scientists from academic centres and from industry and uses a consensus procedure for establishing standards on the basis of the scientific data, followed by an educational programme to ensure that the standards are adopted worldwide. ICSH defines material standards and standardized methods. Material standards are classified as primary international standards, certified reference materials, secondary standards and calibrators. These must be distinguished from control preparations which are intended exclusively for quality control. Standardization of methods must also be considered at four levels: definitive, reference, selected and routine. Each has a place in practice but their roles must be clearly defined. ICSH has an established protocol for evaluation of automated blood cell counters. This defines the levels of precision and accuracy of instrument performance. It is also necessary to assess "clinical utility". The main requirement of the practising haematologist is clinical reliability and harmonization of results for comparability. One of the major functions of ICSH is to provide an interface for collaboration between the manufacturers who develop the instruments and the users in order to achieve this goal.

Coupling of H1 to a central laboratory computer, automated evaluation of instrument alarms

Everyone who has worked with an H1 from Technicon knows that it pours out a vast number of asterisks and error flags and that the same information is hidden in different places. After comparing a great number of samples from H1 with manual methods, we found that we could reduce the number of alarms of medical significance to about 20. So we built a microcomputer which sends the test results, the asterisks and 20 user defined alarm flags to the host computer where the verification takes place. The verification program automatically approves of tests where no alarms, asterisks or high or low values occur. Tests with any kind of alarm or asterisk are displayed. Doubtful results are automatically deleted following specified rules, the meaning of the asterisks can be studied on a switch-screen like on H1, and the technician can take the appropriate action, microscopy, rerun or checking H1.

Flow cytometry applications for exotic animals

This article describes applications of flow cytometry in hematology. It includes a basic description of how flow cytometers work and their use in enumerating cell populations based on phenotypic markers and measurement of cell functions. Challenges presented by limitations of reagents for exotic animals are described in addition to sources of cross-reactive antibodies.

Comparative evaluation of haemoglobin estimation amongst pregnant women in Ibadan: Hemocue - B haemoglobin analyzer versus haemiglobincyanide (standard) method as the gold standard

This was a comparative crossectional study that was conducted among 557 antenatal women at the University College Hospital, Ibadan, Nigeria between 1st April and 30th May 2006. The study compared the accuracy of haemoglobin estimation using an automated HemoCue B analyzer kit with a standard laboratory method (haemogloincyanide) as the gold standard. The result showed a positive correlation of HaemoCue haemoglobin results when compared with the standard methods (Pearson's correlation coefficient = 0.892; p value = 0.000). We concluded that the use of the automated HemoCue kit for haemoglobin estimation gives an objective assessment which overcomes the challenge of extra skilled manpower or power outages in rural areas thereby enhancing access to quality of care in resource poor countries.

An assessment of the Coulter Counter Models S Plus II and III

The Coulter Counter Models S Plus II and III have been evaluated. No serious safety hazards were identified. Scientific assessment showed some non-linearity in the Hb which caused the MCH and MCHC to vary as samples were diluted. Precision and carry-over were satisfactory. The results obtained compared well with those of the Coulter Counter Model S, except for WBC; reference methods showed better accuracy on the Models S Plus II and III. Platelet counts agreed with those by phase-contrast microscopy and the lymphocyte percentage was similar to that from the blood film except in the lymphoproliferative disorders. The whole blood and pre-dilute modes gave similar results though the platelet count was slightly higher in the whole blood mode. In the National External Quality Assessment Scheme results were in accordance with those from other Model S Plus Users. Time did not allow a detailed evaluation of the cell volume distribution curves but it was noted that the white cell profile was useful for detecting platelet aggregation. Efficiency assessment showed throughputs of 66 and 93 samples per hour on the Models S Plus II and III respectively. The platelet count was clinically useful as was the lymphocyte percentage measurement which rendered some differentials unnecessary. Rejection of the white cell profile was a helpful index of abnormality on the Model S Plus II but occurred non-specifically on the Model III tested.

PCV measurement in the management of polycythaemic patients

The PCV of samples from normal individuals and polycythaemic patients being treated by venesection were measured using the microhaematocrit corrected for trapped plasma, radio-isotope dilution, the Coulter 'S' and Coulter 'S Plus'. There was no significant difference between the two manual methods for either the normal individuals or the polycythaemic patients. The Coulter S and S Plus gave lower values for PCV compared with the corrected microhaematocrit, particularly for the polycythaemic patients. The underestimation of the PCV by the Coulter instruments for the polycythaemic group was significantly related to the MCH and MCV. The under-estimation was approximately 6.4% and 7.4% at an MCH of 20 pg by the Coulter S and S Plus respectively. These findings have relevance to the management of polycythaemia by venesection if the effectiveness of treatment is monitored by measuring the PCV by a Coulter instrument.

The Coulter Counter Model S Plus--the shape of things to come

The Coulter Counter Model S Plus is a 12 parameter haematological analyser designed for service use in haematology laboratories. Eight parameters are standard in current routine haematological practice; the seven parameters generated by the Model S and a platelet count. The method of platelet counting is unique. The remaining parameters are new and comprise the platelet-crit, the mean platelet volume and size distribution measurements for both platelets and red cells. A description of the instrument is given including differences from the Model S. The new parameters are discussed in detail. Instrument precision is assessed in terms of linearity, reproducibility, drift, carry-over and protein build-up. The results of all are impressive. Instrument accuracy is assessed in detail; white cell count, red cell count, haemoglobin concentration and mean corpuscular volume being compared with those values measured by the Model S; the Model S Plus haematocrit is compared with the microhaematocrit and platelet counts with those from the Thrombocounter C/Thrombofuge system. All correlations are very satisfactory. Normal values are defined for the new parameters. Instrument design and function are assessed and reagent consumption quoted. Cell control reagents have been evaluated. A realistic hourly throughput for the Model S Plus is 70-80 samples.

Protocol for evaluation of automated blood cell counters. International Committee for Standardization in Haematology (ICSH)

This protocol is proposed for the evaluation of automated blood cell counters to assess the performance, advantages and limitations of such instruments. It is based on the International Committee for Standardization in Haematology (ICSH) 'Protocol for type testing equipment and apparatus used for haematological analysis' (1978a) and the British Committee for Standardization in Haematology 'Guidelines for the evaluation of instruments used in haematology' (Shinton, England & Kennedy, 1982). The document has been prepared by the ICSH Panel on Cytometry after discussion with colleagues. This tentative protocol will be reviewed 1 year after publication, in accordance with the ICSH rules, before it is adopted as a definitive standard.