Performance comparison of two automated digital morphology analyzers for leukocyte differential in patients with malignant hematological diseases: Mindray MC-80 and Sysmex DI-60

BACKGROUND

The MC-80 (Mindray, Shenzhen, China), a newly available artificial intelligence (AI)-based digital morphology analyzer, is the focus of this study. We aim to compare the leukocyte differential performance of the Mindray MC-80 with that of the Sysmex DI-60 and the gold standard, manual microscopy.

METHODS

A total of 100 abnormal peripheral blood (PB) smears were compared across the MC-80, DI-60, and manual microscopy. Sensitivity, specificity, predictive value, and efficiency were calculated according to the Clinical and Laboratory Standards Institute (CLSI) EP12-A2 guidelines. Comparisons were made using Bland-Altman analysis and Passing-Bablok regression analysis. Additionally, within-run imprecision was evaluated using five samples, each with varying percentages of mature leukocytes and blasts, in accordance with CLSI EP05-A3 guidelines.

RESULTS

The within-run coefficient of variation (%CV) of the MC-80 for most cell classes in the five samples was lower than that of the DI-60. Sensitivities for the MC-80 ranged from 98.2% for nucleated red blood cells (NRBC) to 28.6% for reactive lymphocytes. The DI-60's sensitivities varied between 100% for basophils and reactive lymphocytes, and 11.1% for metamyelocytes. Both analyzers demonstrated high specificity, negative predictive value, and efficiency, with over 90% for most cell classes. However, the DI-60 showed relatively lower specificity for lymphocytes (73.2%) and lower efficiency for blasts and lymphocytes (80.1% and 78.6%, respectively) compared with the MC-80. Bland-Altman analysis indicated that the absolute mean differences (%) ranged from 0.01 to 4.57 in MC-80 versus manual differential and 0.01 to 3.39 in DI-60 versus manual differential. After verification by technicians, both analyzers exhibited a very high correlation (r = 0.90-1.00) with the manual differential results in neutrophils, lymphocytes, and blasts.

CONCLUSIONS

The Mindray MC-80 demonstrated good performance for leukocyte differential in PB smears, notably exhibiting higher sensitivity for blasts identification than the DI-60.

Daily monitoring of vaginal interleukin 6 as a predictor of intraamniotic inflammation after preterm premature rupture of membranes - a new method of sampling studied in a prospective multicenter trial

OBJECTIVES

(A) To introduce a new technique for vaginal fluid sampling (biocompatible synthetic fiber sponge) and (B) evaluate the collected vaginal fluid interleukine-6 (IL-6_vag)-concentration as a new diagnostic tool for daily monitoring of intrauterine inflammation after preterm premature rupture of membranes (PPROM). Secondary objectives were to compare the potential to predict an intrauterine inflammation with established inflammation parameters (e.g., maternal white blood cell count).

METHODS

This prospective clinical case-control diagnostic accuracy multicenter study was performed with women after PPROM (gestational age 24.0/7 - 34.0/7 weeks). Sampling of vaginal fluid was performed once daily. IL-6_vag was determined by electrochemiluminescence-immunoassay-kit. Neonatal outcome and placental histology results were used to retrospectively allocate the cohort into two subgroups: 1) inflammation and 2) no inflammation (controls).

RESULTS

A total of 37 cases were included in the final analysis. (A): Measurement of IL-6 was successful in 86% of 172 vaginal fluid samples. (B): Median concentration of IL-6_vag in the last vaginal fluid sample before delivery was significantly higher within the inflammation group (17,085 pg/mL) compared to the controls (1,888 pg/mL; p=0.01). By Youden's index an optimal cut-off for prediction an intrauterine inflammation was: 6,417 pg/mL. Two days before delivery, in contrast to all other parameters IL-6_vag remained the only parameter with a sufficient AUC of 0.877, p<0.001, 95%CI [0.670-1.000].

CONCLUSIONS

This study established a new technique for vaginal fluid sampling, which permits assessment of IL-6_vag concentration noninvasively in clinical daily routine monitoring.

Spurious Low WBC Count from Sysmex XN3000: a Case Report

BACKGROUND

We present a case of spurious low WBC count in a liver transplant patient. The patient is a 56-year-old man with liver cancer.

METHODS

His routine blood test revealed a decrease in WBC count: 0.03 x 109/L compared to 19.30 x 109/L before. The WBCs in the blood smear appeared higher than that reported by the XN without any aggregation. We diluted the blood sample to 1:7 with the DCL of the XN.

RESULTS

The diluted result matches the blood smear.

CONCLUSIONS

Dilution mode may be a good choice when there is WNR and WDF discordance, and a smear must be reviewed.

The Diagnostic Performance of Urine Flow Cytometer UF1000i for Urinary Tract Infections

BACKGROUND

Urinary tract infections (UTIs) are one of the most common infectious diseases in clinic. Urine flow cytometry is receiving more and more attention due to its rapid forecast of UTIs.

METHODS

The Urine Flow Cytometer UF1000i has a series of software programs to quantify bacteria (BACT) and white blood cells (WBC), and describe the scatter diagram of bacteria. The UTIs were predicted based on the cutoff values with the Receiver Operating Characteristic (ROC) curves of BACT and WBC counts. To evaluate the diagnostic performance of UF1000i for UTIs, the sensitivity and specificity of 889 urine samples were determined in comparison to the results of urine culture. Meanwhile the bacterial morphology indication of the UF1000i was evaluated in order to help doctors choose antibiotics. The angle of the scatter cloud with the x-axis was used to classify the infected bacteria as bacilli (< 30°) or cocci (≥ 30°).

RESULTS

The best cutoff value of BACT counts for predicting UTIs was 119 per µL, and the sensitivity and specificity were 95.5% and 88.7%, respectively. While the best cutoff value of WBC counts was 81.5 per µL, and the sensitivity and specificity were 77.6% and 76.7%, respectively. In addition, the best cutoff values for females were 583 BACT per µL and 137.5 WBC per µL. They were much higher than for males (118 BACT per µL and 91 WBC per µL). The coincidence of the bacterial morphology information between the UF1000i software indication and the bacterial actual morphology identified by urine culture was 83% (bacilli) and 68% (cocci), respectively.

CONCLUSIONS

Data demonstrated that the performance of BACT counts for UTIs is superior to WBC counts. In addition, the bacterial morphology could preliminarily be predicated by the scatter diagram. Since the urine flow cytometer UF1000i can provide the data of both BACT counts and the scatter diagram, the urine flow cytometry was regarded as a suitable method for screening UTIs. Moreover, it would be better to take gender into consideration when setting the best cutoff value for diagnosis of UTIs in clinic.

Multivariate computational analysis of biosensor's data for improved CD64 quantification for sepsis diagnosis

Sepsis, as a leading cause of death worldwide, relies on systemic inflammatory response syndrome (SIRS) criteria for its diagnosis. SIRS is highly non-specific as it relies on monitoring of patients' vitals for sepsis diagnosis, which are known to change with many confounding factors. Changes in leukocyte counts and CD64 expression levels are known specific biomarkers of pro-inflammatory host response at the onset of sepsis. Recently, we have developed a biosensor chip that can enumerate the leukocyte counts and quantify the neutrophil CD64 expression levels from a drop of blood. We were able to show improved sepsis diagnosis and prognosis in clinical studies by measuring these parameters during different times of the patients' stay in hospital. In this paper, we investigated the rate of cell capture with CD64 expression levels and used this in a multivariate computational model using artificial neural networks (ANNs) and showed improved accuracy of quantifying CD64 expression levels from the biosensor (n = 106 whole blood experiments). We found a high coefficient of determination and low error between biosensor- and flow cytometry-based neutrophil CD64 expression levels using multiple ANN training methods in comparison to those of univariate regression commonly employed. This approach can find many applications in biosensor data analytics by utilizing multiple features of the biosensor's data for output determination.

Novel flowcytometry-based approach of malignant cell detection in body fluids using an automated hematology analyzer

Morphological microscopic examinations of nucleated cells in body fluid (BF) samples are performed to screen malignancy. However, the morphological differentiation is time-consuming and labor-intensive. This study aimed to develop a new flowcytometry-based gating analysis mode “XN-BF gating algorithm” to detect malignant cells using an automated hematology analyzer, Sysmex XN-1000. XN-BF mode was equipped with WDF white blood cell (WBC) differential channel. We added two algorithms to the WDF channel: Rule 1 detects larger and clumped cell signals compared to the leukocytes, targeting the clustered malignant cells; Rule 2 detects middle sized mononuclear cells containing less granules than neutrophils with similar fluorescence signal to monocytes, targeting hematological malignant cells and solid tumor cells. BF samples that meet, at least, one rule were detected as malignant. To evaluate this novel gating algorithm, 92 various BF samples were collected. Manual microscopic differentiation with the May-Grunwald Giemsa stain and WBC count with hemocytometer were also performed. The performance of these three methods were evaluated by comparing with the cytological diagnosis. The XN-BF gating algorithm achieved sensitivity of 63.0% and specificity of 87.8% with 68.0% for positive predictive value and 85.1% for negative predictive value in detecting malignant-cell positive samples. Manual microscopic WBC differentiation and WBC count demonstrated 70.4% and 66.7% of sensitivities, and 96.9% and 92.3% of specificities, respectively. The XN-BF gating algorithm can be a feasible tool in hematology laboratories for prompt screening of malignant cells in various BF samples.

New Alert Message Settings for the XN-series Automated Hematology Analyzer Are Useful for Avoiding Falsely High WBC Counts and to Detect Specimens with Giant Platelets

We encountered blood specimens from a patient with MYH9 related diseases, which gave falsely high white blood cell (WBC) counts during laboratory analysis using Sysmex XN-series automated hematology analyzers. This overcount was revealed to be caused by the overlapping of platelet (PLT) distribution with the WBC area in the WNR channel, which was used for routine WBC count with the XN-series. On the other hand, the WBC count obtained through the WDF channel of the XN-series seemed more accurate in such a case. We then created and introduced alert message settings for such rare but critical specimens, which gives a warning when the discrepancy in WBC counts between the WNR and WDF channels is higher than 1.0×10⁹/L. By using the alert message setting, we were able to detect some specimens which gave falsely high WBC counts with the routine WNR channel from three other cases of giant PLTs. In conclusion, our alert message setting seems useful in avoiding false reporting of WBC count due to abnormal cells, including giant PLTs.

A New Automated Technology for Cerebrospinal Fluid Cell Counts: Comparison of Accuracy and Clinical Impact of GloCyte, Sysmex XN, and Manual Methods

OBJECTIVES

The purpose of the study was to compare the performance of GloCyte (Advanced Instruments, Norwood, MA), a new semiautomated instrument for cerebrospinal fluid cell counting, with the manual hemocytometer method and the automated Sysmex XN (Sysmex, Kobe, Japan) body fluid mode. The clinical impact of replacing the manual method with either automated method was determined.

METHODS

Fifty-seven samples from 38 patients were analyzed by all three methods. Pearson correlation and Passing-Bablok regression were used to compare methods. Cytospin smears were reviewed on all samples, and clinical histories were obtained.

RESULTS

There was a strong linear relationship between the manual and automated methods for WBC counts ( R  = 0.988 for GloCyte; R  = 0.980 for Sysmex XN). Positive bias was absent or negligible for WBC counts less than 30/μL. GloCyte and manual RBC counts were equivalent. There were no samples for which replacement of manual WBC counts by automated counts would have changed the diagnosis. Both automated methods showed improved precision for WBC counts compared with the manual method.

CONCLUSIONS

Replacing manual WBC counts by GloCyte or Sysmex XN WBC counts would improve consistency of results without compromising diagnostic accuracy.

Application of a portable microscopic cell counter for the counting of residual leukocytes in leukoreduced apheresis platelet concentrates in a hospital blood bank

While a portable microscopic cell counter has been evaluated to enumerate residual white blood cells (WBCs) in red blood cells and platelet concentrates at blood centers, it has not yet been assessed in a hospital blood bank. We investigated the performance of this device and evaluated its accuracy, along with its benefits in time management. Residual WBCs from each of 100 apheresis platelet specimens were measured manually using a Nageotte chamber, along with flow cytometry methods and an ADAM-rWBC automated instrument (NanoEnTek, Seoul, South Korea). The efficiency was calculated by measuring the time required for the analysis of one specimen ten times consecutively. Flow cytometry and the ADAM-rWBC were able to detect four sporadic cases that had residual WBCs exceeding 1/μL that were not detected by the manual method. Analysis time was the shortest with the ADAM-rWBC, followed by flow cytometry and the manual method. Our data suggest that hospital blood banks require quality control of residual WBCs; among the methods evaluated in this study, the portable microscopic cell counter offers the best time efficiency.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Basic Evaluation of Microsemi LC-767CRP as POCT Model for Simultaneous Measurement of CBC and CRP]

Microsemi LC-767CRP (LC-767, Horiba, Ltd.) is capable of simultaneous measuring of complete blood count (CBC) including 3-part differentials (3-part Diff.) of white blood cells (WBC) and C-reactive protein (CRP) in 4 minutes. Data obtained using LC-767 were intra-assay-reproducible (n = 10, CV = 0.6-4.0% for CBC, 0.6-2.5% for 3-part Diff. and 2.8-7.7% for CRP). They also showed the good linearity, no definite carry-over and the excellent correlations with routine instruments in our institution. Concerning CRP, the minimal detectable concentration revealed < 0.1 mg/dL, and prozone was observed in the sample containing > 30 mg/dL of CRP. LC-767 showed better correlation with a routine instrument in monocyte percentage than LC-667, probably due to modification of the hemolysis solution ratio and diluent temperature. In conclusion, LC-767 provided accurate CBC and CRP results, and showed improvement in CRP linearity and monocyte percentage compared with LC-667. LC-767, which is equipped with a bar-code reader with easy accessibility to electronic medical record, is suitable as the next-generation point of care testing model in the era of information and network-oriented medicine.

[The Utility of XE-2 100 Analyzer's NEUT-X and NEUT-Y Parameters for Detecting Neutrophil Dysplasia in Myelodysplastic Syndromes]

Morphological abnormalities of blood cells are the typical characteristics of myelodysplastic syndromes (MDS). Recently, the usefulness of multiparameter automatic hematology analyzer XE-2100 for detecting neutrophil dysplasia has been reported by using parameters of NEUT-X and NEUT-Y, reflecting neutrophil cytoplasmic granularity and the cellular content of nucleic acid and protein, respectively. We evaluated the utility of these parameters by analyzing the blood samples of fifty MDS patients consulting Kakogawa West Municipal Hospital between Jan, 2010 and Jun, 2014, as well as 100 persons undergoing medical examinations during the same period as controls. Neutrophil granulation level was classified as normal, hypo-granular, or agranular under microscopic observation, and degranulation index was calculated using the following formula. The relationship between NEUT-X, NEUT-Y values and degranulation index was studied as below. Degranulation index = agranular (%) x 2+ hypo-granular (%) x 1 + normal (%) x 0 Neut-X values of MDS patients were 1,350 (mean), 1,345 (median), and NEUT-Y values, 430 (mean) and 432 (median). The NEUT-X and NEUT-Y values of control patients were 1,350, 1,349, 446 and 445, respectively. Correlation efficiency between degranulation index and NEUT-X or NEUT-Y were r = 0.62 or 0.52, respectively. Relationship between NEUT-X and NEUT-Y for all patients was r = 0.90. All the 10 patients showing NEUT-X lower than 1,315 and NEUT-Y lower than 400 simultaneously were MDS. Hence, we conclude that NEUT-X and NEUT-Y information is useful for quantitative evaluation of neutrophil morphological abnormalities.

On-chip sample preparation for complete blood count from raw blood

This paper describes a monolithic microfluidic device capable of on-chip sample preparation for both RBC and WBC measurements from whole blood. For the first time, on-chip sample processing (e.g. dilution, lysis, and filtration) and downstream single cell measurement were fully integrated to enable sample preparation and single cell analysis from whole blood on a single device. The device consists of two parallel sub-systems that perform sample processing and electrical measurements for measuring RBC and WBC parameters. The system provides a modular environment capable of handling solutions of various viscosities by adjusting the length of channels and precisely controlling mixing ratios, and features a new 'offset' filter configuration for increased duration of device operation. RBC concentration, mean corpuscular volume (MCV), cell distribution width, WBC concentration and differential are determined by electrical impedance measurement. Experimental characterization of over 100,000 cells from 10 patient blood samples validated the system's capability for performing on-chip raw blood processing and measurement.

"Aged sample" software on automated routine hematology analyzer enables differentiation between pathological and non-pathological WBC flagging in aging samples

BACKGROUND

Storing K(x)EDTA-conjugated blood samples at room temperature or under insufficient cooling conditions results in various morphological changes such as swelling of the blood cells. These changes are reproducible and have already been described well. However, they can lead to incorrect flagging when using automated hematology analyzers for complete blood counts and white blood cell differentials. The aim of this study was to determine if those changes can be detected automatically and used to prevent false positive flagging.

METHODS

150 blood samples were aged under controlled conditions and the impact on the "Aged sample" software was checked retrospectively. The results were verified in a second retrospective study including 6288 routine samples.

RESULTS

When tested in a routine laboratory, the "Aged sample" software was able to reduce overall flagging by 23% without increasing false negative flagging.

CONCLUSIONS

The "Aged sample" software of XN-Series analyzers does not only detect and flag samples that are aging or were stored under suboptimal conditions but also prevents false positive flagging.

Automated cell analysis of cerebrospinal fluid with XE-5000

BACKGROUND

Hematology analyzers have been able to make automated counts of cells present in CSF samples in recent years. Most of them cannot provide reliable counts of the low cell levels usually present in CSF.

METHODS

Functional sensitivity, precision, analytical measurement range, and method comparisons were deter- mined according to Clinical Laboratory Standards Institute (CLSI) guidelines.

RESULTS

The functional sensitivity for white blood cells (WBC) and red blood cells (RBC) was 18/μL and 725/μL (minimum reported concentration), respectively. The total precision ranged from 6.1% to 16.3% for WBC counts within the concentration of 33-183/μL and from 4.1% to 19.4% for RBC counts within the concentration of 745-11,350/μL. The within-run precision for WBC was 3.1% at 7,592/μL. The analytical measurement range was 18-10,078/μL for WBC and 725-5,222,550/μL for RBC. There was good correlation between WBC and RBC counts determined by the XE5000 and microscopic examination, according to slopes and R2 method comparisons. The correlation of the two methods for mononuclear cell (MN) counts was 0.907 with the WBC count of 50-5,000/μL. The reliability of WBC counts produced by the XE-5000 was 0.7.

CONCLUSIONS

The XE-5000 performed satisfactorily in the CSF assay, but it is still necessary to manually confirm the WBC count when it is less than 18/μL.

Opto-fluidics based microscopy and flow cytometry on a cell phone for blood analysis

Blood analysis is one of the most important clinical tests for medical diagnosis. Flow cytometry and optical microscopy are widely used techniques to perform blood analysis and therefore cost-effective translation of these technologies to resource limited settings is critical for various global health as well as telemedicine applications. In this chapter, we review our recent progress on the integration of imaging flow cytometry and fluorescent microscopy on a cell phone using compact, light-weight and cost-effective opto-fluidic attachments integrated onto the camera module of a smartphone. In our cell-phone based opto-fluidic imaging cytometry design, fluorescently labeled cells are delivered into the imaging area using a disposable micro-fluidic chip that is positioned above the existing camera unit of the cell phone. Battery powered light-emitting diodes (LEDs) are butt-coupled to the sides of this micro-fluidic chip without any lenses, which effectively acts as a multimode slab waveguide, where the excitation light is guided to excite the fluorescent targets within the micro-fluidic chip. Since the excitation light propagates perpendicular to the detection path, an inexpensive plastic absorption filter is able to reject most of the scattered light and create a decent dark-field background for fluorescent imaging. With this excitation geometry, the cell-phone camera can record fluorescent movies of the particles/cells as they are flowing through the microchannel. The digital frames of these fluorescent movies are then rapidly processed to quantify the count and the density of the labeled particles/cells within the solution under test. With a similar opto-fluidic design, we have recently demonstrated imaging and automated counting of stationary blood cells (e.g., labeled white blood cells or unlabeled red blood cells) loaded within a disposable cell counting chamber. We tested the performance of this cell-phone based imaging cytometry and blood analysis platform by measuring the density of red and white blood cells as well as hemoglobin concentration in human blood samples, which showed a good match to our measurement results obtained using a commercially available hematology analyzer. Such a cell-phone enabled opto-fluidics microscopy, flow cytometry, and blood analysis platform could be especially useful for various telemedicine applications in remote and resource-limited settings.

Four-part leukocyte differential count based on sheathless microflow cytometer and fluorescent dye assay

Leukocyte differential count is one of the most frequently ordered clinical tests in hospitals. This paper reports a point-of-care test for the leukocyte count by using a microflow cytometer and a fluorescent dye assay. The dye assay relied on fluorescent detection alone to count leukocytes in blood and to identify leukocyte subtypes. By combining the fluorescent assay with a sheathless microflow design, the proposed method achieved a minimal sample volume by eliminating excessive dilution and sheath flow. In this paper, a four-part leukocyte differential count including lymphocyte, monocyte, neutrophil and eosinophil was demonstrated, and the whole test consumed only a small amount of blood (5 μL) and reagents (68 μL in total). The merits of minimal sample volume, long reagent shelf life and portable instrument made this method optimal for point-of-care applications.

[Evaluation of a UF-1000i screening method to identify the bacteriuria for cultures and susceptibility testing]

Urine culture remains the gold standard for diagnosing urinary tract infections, but most clinical samples yield negative results. Fast screening methods will improve the turnaround time and also reduce the associated costs. We evaluated the detection of bacteria using the Sysmex UF-1000i urine analyzer to identify negative samples which do not need further culture testings. The bacterial counts of the UF-1000i method and of the conventional culture of 197 samples, including 117 samples of midstream urine (MU) and 80 from catheter ports (CU), were prospectively compared, and the patient backgrounds were reviewed. The cut-off values to determine the necessity for culture were 2.7 bacteria/microL for MU and 11.0 bacteria/microL for CU samples, and 16.2% of the MU and 30.0% of the CU samples did not require cultures. These cut-off values are similar to those described in previous studies, however, our findings suggest that it would therefore be possible to reduce the need for unnecessary samples by the use of our cut-off values, which utilize the CU and MU samples separately. The cost reduction was calculated to be $239-306 per 100 samples. This UF-1000i screening method is an acceptable modality which improves the turnaround time, workload and cost to perform urine cultures.

Comparison of venous and capillary differential leukocyte counts using a standard hematology analyzer and a novel microfluidic impedance cytometer

Capillary blood sampling has been identified as a potentially suitable technique for use in diagnostic testing of the full blood count (FBC) at the point-of-care (POC), for which a recent need has been highlighted. In this study we assess the accuracy of capillary blood counts and evaluate the potential of a miniaturized cytometer developed for POC testing. Differential leukocyte counts in the normal clinical range from fingerprick (capillary) and venous blood samples were measured and compared using a standard hematology analyzer. The accuracy of our novel microfluidic impedance cytometer (MIC) was then tested by comparing same-site measurements to those obtained with the standard analyzer. The concordance between measurements of fingerprick and venous blood samples using the standard hematology analyzer was high, with no clinically relevant differences observed between the mean differential leukocyte counts. Concordance data between the MIC and the standard analyzer on same-site measurements presented significantly lower leukocyte counts determined by the MIC. This systematic undercount was consistent across the measured (normal) concentration range, suggesting that an internal correction factor could be applied. Differential leukocyte counts obtained from fingerprick samples accurately reflect those from venous blood, which confirms the potential of capillary blood sampling for POC testing of the FBC. Furthermore, the MIC device demonstrated here presents a realistic technology for the future development of FBC and related tests for use at the site of patient care.

Development and testing of a new disposable sterile device for labelling white blood cells

AIM

White blood cell (WBC) labelling requires isolation of cells from patient's blood under sterile conditions using sterile materials, buffers and disposables under good manufacturing practice (GMP) conditions. Till now, this limited the use of white blood cell scintigraphy (WBC-S) only to well equipped laboratories with trained personnel. We invented, developed and tested a disposable, sterile, closed device for blood manipulation, WBC purification and radionuclide labelling without exposing patient's blood and the operator to contamination risks. This device prototype and a final industrialized device (Leukokit®) were tested for WBC labelling and compared to standard procedure. Leukokit® was also tested in an international multi-centre study for easiness of WBC purification and labelling.

METHODS

On the device prototype we tested in parallel, with blood samples from 7 volunteers, the labelling procedure compared to the standard procedure of the International Society of Radiolabeled Blood Elements (ISORBE) consensus protocol with respect to cell recovery, labelling efficiency (LE), cell viability (Trypan Blue test) and sterility (haemoculture). On the final Leukokit® we tested the biocompatibility of all components, and again the LE, erythro-sedimentation rate, cell viability, sterility and apyrogenicity. ACD-A, HES and PBS provided by Leukokit® were also compared to Heparin, Dextran and autologous plasma, respectively. In 4 samples, we tested the chemotactic activity of purified WBC against 1 mg/ml of lipopolysaccharide (LPS) and chemotaxis of 99mTc-HMPAO-labelled WBC (925 MBq) was compared to that of unlabelled cells. For the multi-centre study, 70 labellings were performed with the Leukokit® by 9 expert operators and 3 beginners from five centers using blood from both patients and volunteers. Finally, Media-Fill tests were performed by 3 operators on two different days (11 procedures) by replacing blood and kit reagents with bacterial culture media (Tryptic Soy Broth) and testing sterility of aliquots of the medium at the end of procedure.

RESULTS

Tests performed with the prototype showed no significant differences with the standard procedure but a faster and safer approach. Tests performed with the final Leukokit® confirmed full biocompatibility, sterility and apyrogenicity of all reagents and plastic ware. Average WBC recovery with Leukokit® was comparable to that of the ISORBE protocol (117x106±24x106 vs. 132x106±29x106 cells, P=not significant). No differences in red blood cells and platelet content were observed. LE was 82% ± 3% for Leukokit® and 65±5% for control (P=0.0003) being PBS vs autologous plasma the main reason of such difference. Cell viability was always >99.9% in both conditions. Chemotactic tests showed no differences between all Leukokit® samples and controls. Haemocultures and Media-Fill tests were always sterile. The procedure was well accepted by expert operators and beginners, with a very fast learning curve (confidence after 2±2 labellings).

CONCLUSION

The invented device offers high level of protection to operators and patients. The derived Leukokit® is safe and easy to use, and gives a high LE of WBC without affecting cell viability and function. Being a registered closed, sterile medical device, it may allow easier and faster WBC labelling that is not limited to only well equipped laboratories. Also simultaneously labelling of multiple patients is possible.

[Scepter--the use of automated cell counter in quantitative and qualitative analysis of human peripheral blood mononuclear cells]

Scepter is easy to use and convenient tool for rapid cell counting in in vitro culture. Quantitative and qualitative results are presented immediately after the measurement on its screen. So far, Bürker's chamber was most commonly used for the counting of cells. Due to the presence of a small display, Scepter as the flow cytometers reveals data on cell diameter and volume in the form of histograms. It facilitates the differentiation of various cell populations in the studied samples. This article presents experiments designed to isolate and compare peripheral blood mononuclear cells (PBMCs) from children and adults. To this end, the both of mentioned tools were used.

[Performance evaluation of the CellaVision DM96 system in WBC differentials]

Though differential counting of peripheral blood cells is an important diagnostic tool, this technique requires highly trained staff. Automation of differentials is desirable for economic and time-saving reasons. Recently, the CellaVision DM96 (DM96, CellaVision AB, Lund, Sweden) has been introduced as an automated cell analysis system capable of morphological classification of WBCs and RBCs in pheripheral blood smears. In this study, we routinely analyzed the blood samples from 216 patients by the DM96. The overall preclassification of WBC analysis accuracy value for the DM96 was 90.3%. Good correlation coefficients between final results of the DM96 and manual differentiation were observed. The DM96 system performed high sensitivity and specificity for blasts and immature granulocytes. Although the DM96 system operates more effectively in the normal blood samples than pathological ones, its ability of review slides on the computer screen with a cell-by-cell basis provides real-time collaboration between colleagues when they face the abnormal cells.

Leukocyte analysis and differentiation using high speed microfluidic single cell impedance cytometry

Miniature high speed label-free cell analysis systems have yet to be developed, but have the potential to deliver fast, inexpensive and simple full blood cell analysis systems that could be used routinely in clinical practice. We demonstrate a microfluidic single cell impedance cytometer that performs a white blood cell differential count. The device consists of a microfluidic chip with micro-electrodes that measure the impedance of single cells at two frequencies. Human blood, treated with saponin/formic acid to lyse erythrocytes, flows through the device and a complete blood count is performed in a few minutes. Verification of cell dielectric parameters was performed by simultaneously measuring fluorescence from CD antibody-conjugated cells. This enabled direct correlation of impedance signals from individual cells with phenotype. Tests with patient samples showed 95% correlation against commercial (optical/Coulter) blood analysis equipment, demonstrating the potential clinical utility of the impedance microcytometer for a point-of-care blood analysis system.

External quality assessment of automated blood leukocyte differential counts and other simultaneous measured quantities

An external quality assessment scheme (EQAS) of automated differential counts of leukocytes has been carried out using selected fresh blood specimens. The measurements were carried out one day after blood drawing because of the delay in the mail. Reference laboratories established target values for differential counts. They counted visually 600-700 cells in each specimen on smears. The consensus value among 12 laboratories for manual count of total leukocytes was used as target value, but was found on average 9% smaller than the average instrumental value. H1 results compared favorable with the target value for the differentials. The less advantageous findings on Coulter S + IV are partly explained by the age of the specimen when measured. The data indicated that better calibration of the instruments could decrease the overall variation of platelets counts and haemoglobin determinations. An EQAS involving measurement on fresh specimens is in progress.

Improved automated differential counts of leukocytes from newborn infants using pre-dilution of blood samples

A method for automated differential leukocyte counting using peroxidase staining and light scatter (H1) failed to present results in more than 25% of blood samples from newborn infants. These failures were mostly seen at or below 2 weeks of age, and with high concentrations of haemoglobin F (HbF). Dilution of the blood with equal amounts of isotonic saline made the problem disappear almost completely. The results of differential counts on such diluted blood samples also compared more favourably with traditional manual counts of blood smears than did the results obtained with undiluted blood. The present method with blood diluted 1/2 is therefore recommended for routine use in newborn infants.

Automated differential leukocyte counts in newborn infants. Comparison of Coulter VCS and Technicon H1 with manual counts

There was good agreement between results obtained with Coulter VCS/Technicon H1 and manual counting with respect to neutrophils and eosinophils. Coulter VCS overestimates the lymphocyte percentage compared to manual counting and to H1. If, however, the percentage of so called "naked" cells are added to the percentage of manually counted lymphocytes, the agreement between VCS and the manual method is improved. The alarms given by the two instruments are of little value in detecting left shift or nucleated red blood cells.

Comparison of four hematology analyzers, CELL-DYN Sapphire, ADVIA 120, Coulter LH 750, and Sysmex XE-2100, in terms of clinical usefulness

We evaluated the clinical usefulness (leukocyte distribution classification, morphologic classification, and morphologic flags) of the following four hematology analyzers: CELL-DYN Sapphire (CD-Sapphire) (Abbott Diagnostics, Santa Clara, CA, USA), ADVIA 120 (Bayer Diagnostics, Tarrytown, NY, USA), Beckman Coulter LH 750 (Beckman Coulter, Miami, FL, USA), and Sysmex XE-2100 (TOA Medical Electronics Co., Kobe, Japan). Four hundred thirty samples from patients and 100 samples from healthy individuals were analyzed. For distributional classification, the sensitivity rates of CD-Sapphire, ADVIA 120, LH 750, and XE-2100 were 93.1, 95.9, 94.9, and 94.9%, respectively, and the efficiency rates were 80.7, 81.6, 84.1, and 84.2%, respectively. For morphologic classification, the sensitivity rates of CD-Sapphire, ADVIA 120, LH 750, and XE-2100 were 88.6, 93.2, 77.3, and 94.3%, respectively, and the efficiency rates were 80.9, 73.0, 79.5, and 74.2%, respectively. Comparing the findings in different morphologic flags, XE-2100 showed the highest sensitivity for Blasts flag (90.9%); CD-Sapphire showed the highest sensitivity for Immature granulocytes and/or Left-shift flag (85.5%); ADVIA 120 showed the highest sensitivity for Atypical lymphocytes flag (60.0%); and LH 750 showed the highest sensitivity for Nucleated RBC flag (75.0%). Our results demonstrate that the four analyzers are comparable in overall performance.

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.

Analysis of leucocyte populations with the Coulter S-Plus STKR as a screening tool for haematological abnormalities

In two institutions at Rome and Florence we evaluated the clinical sensitivity of two Coulter STKR systems using the NCCLS standard H20-T for leucocyte differential count in a patient population with high prevalence of haematologic abnormalities. Reference ranges of normal leucocytes were obtained on 278 adult subjects. On a population of 455 patient specimens, 200 specimens (44%) were flagged by the STKR because of a distributional abnormality, and 122 (27%) because of a morphological abnormality. Percentage of subtotal agreements between the STKR and the reference manual differential count was 85.4%, with 67.5% full and 20.9% partial agreements. Eight specimens that showed a morphological abnormality with the reference manual differential count were classified as normal by the STKR, with a false normal rate of 6.6%. Analysis of the STKR performance for morphological abnormalities showed acceptable sensitivity (82.0%) and rather low specificity (71.5%), low predictive value of positive results (51.3), high predictive value of negative results (91.5%) and efficiency of 74.3%. The main problems of the STKR differential count were a high rate of false monocyte count, and the misidentification of eosinophilias and low-concentration abnormal cells.

The estimation of the lymphocyte percentage by the Coulter Counter Model S Plus III

The accuracy of the Coulter Counter Model S Plus III in determining lymphocyte percentage was assessed. In 'routine' adult blood counts accuracy was satisfactory but in infectious mononucleosis, and in chronic lymphocytic leukaemia and other lymphoproliferative disorders, there was a high rejection rate and an often considerable underestimation of the lymphocyte percentage. The S Plus III lymphocyte percentage was of no use in neonates because of inaccuracy and a high rejection rate. In infants the relationship with lymphocyte percentages based on manual differential counts was non-linear, and there was underestimation of some high percentages. The white cell size histogram was useful in altering staff to abnormalities, and also suggested that lymphocytes of neonates and infants were larger than those of adults, with plots being very similar to those of some adults with lymphoproliferative disorders. The S Plus III lymphocyte percentage was useful in reducing the need for differential counts in adult patients but did not replace examination of a blood film or a manual lymphocyte percentage in patients with chronic lymphocytic leukaemia or a lymphoproliferative disorder.

A comparison of differential white cell counting on the Coulter VCS and the Technicon H1 using simple and multiple regression analysis

This study uses the statistical methods of simple and multiple regression to compare the differential white blood count on the Coulter VCS and Technicon H1 analysers. The results demonstrate that both are good at distinguishing lymphocytes, neutrophils and eosinophils. Monocyte differential counts show disappointing correlation, both by simple and multiple regression techniques. Basophils, though less frequently a clinical problem, also correlated poorly in this study.

[Application of comparison method in internal quality control of hematology analyzer by using fresh blood]

OBJECTIVE

To investigate the comparison method on internal control of hematology analyzer by using fresh blood.

METHODS

The hematology analyzer with well function was selected as the reference analyzer, fresh blood samples from healthy subjects were measured by reference analyzer and the values were used to calibrate compared hematology analyzers. The acceptable limits of relative deviation of WBC,RBC, HGB,HCT, PLT were established by comparative experiments during three months. The results of fresh blood samples from patients with low/medium/high levels measured by compared analyzer were compared with those from reference analyzer, the relative deviation of WBC, RBC, HGB, HCT, PLT was calculated respectively. The internal quality control charts in laboratory information system were established, with date as x-axis, relative deviation as y-axis. The acceptable relative deviation limits were set to be +/-2 s, and to be used for laboratory quality control.

RESULT

The relative deviation of WBC, RBC, HGB, HCT, PLT with high, medium, low levels were(0.75+/-2.964)%, (1.19+/-2.488)%,(1.43+/-2.439)%; (-0.39+/-1.327)%, (-0.26+/-1.297)%, (-0.35+/-1.095)%û(-0.43+/-1.393)%, (-0.17+/-1.139)%, (0.24+/-1.166)%û(-.43+/-1.362)%, (-0.36+/-1.381)%, (-0.57+/-1.299)%û(-0.93+/-4.330)%,(0.04+/-4.118)%, (-0.41+/-4.149)%, respectively in 2006. As the second instrument, the compared analyzer was involved in College of American Pathologists Proficiency Testing with satisfactory results, the bias of WBC,RBC, HGB, HCT, PLT were within (-0.5 approximately 5.1)%, (-1.0 approximately 1.6)%, (-1.7 approximately 1.4)%, (-1.5 approximately 1.3)%, (-4.5 approximately 7.4)%, respectively.

CONCLUSION

The quality control on compared hematology analyzer can be effectively, conveniently and economically performed using this method.

Filter selection for five color flow cytometric analysis with a single laser

Flow cytometry has evolved from single- and two-color analysis to the current use of 11-16 colors. The relatively bright excitation spectra of most fluorochromes have made color compensation a challenge especially when performed manually. We describe how by choosing filters with narrower bandwidths results in the color compensation values between FITC, PE, PE-TxR (ECD), PE-Cy5, and PE-Cy7 that range from 0 % to 50% depending on the combination of fluorochromes. Peripheral blood mononuclear cells were stained with alpha-CD4-FITC, alpha-CD27-PE, alpha-CD62L-ECD, alpha-CD45RA-PE-Cy5 and alpha-CD3-PE-Cy7. The samples were acquired on a MO Flo. The initial (first) and second filter sets for our experiments consisted of 530/30 or 519/20 for FITC, 580/30 or 575/20for PE, 630/30 or 630/22 for PE-TxR (ECD), 670/30 or 675/20 for PE-Cy5 and 740LP or 780/40 for PE-Cy7. Nonstained cells were used to adjust the threshold values of detection for each photo multiplier tube (PMT) for each filter set. The mean fluorescent intensity (MFI) of each fluorochrome was not reduced to any great extent by either filter set. However, the compensation value between PE and PE-TxR (ECD) with the first filter selection ranged from 84% to 89% and with the second set of filters it was 25-36%. In addition, the compensation between PE-TxR (ECD) and PE-Cy5 were reduced to 30.2% from 44.2% with the second filter set. The reduction of filter bandwidths that results in minimizing spectral overlaps without lost of signal provides a method by which discrimination of signals between PE containing fluorochromes can be achieved.

Performance evaluation of the Z2 coulter counter for WBC and RBC counting

The Z2 Coulter Counter (Z2) is a new, single-channel semi-automated electronic counter using the Coulter principle, providing both count and concentration results of cells, as well as providing size distribution of the cell population. The Z2 was evaluated according to guidelines published by the International Committee for Standardisation in Haematology. The results demonstrated excellent linearity for WBC and RBC (r > 0.999). The Z2 showed excellent precision, with a within-run, between-run and overall coefficient of variance less than 2%. Carryover was generally acceptable (<1%). WBC and RBC were stable after blood storage for 48 h at 4 degrees C and room temperature. There was almost no interference for WBC, RBC at high concentrations of bilirubin (178.5 mumol/l) or triglyceride (14.8 mmol/l) (P > 0.05). The bias of coincidence correction in WBC and RBC counting with the Z2 was less than 1%. Correlation between the Z2 and Sysmex F-820 or SE-9500 was excellent (r > 0.996) for WBC and RBC counting. Our results indicate that the Z2 has good features of precision, accuracy, linearity and good comparison with other haematology analysers, and could be used as a calibrating instrument for WBC and RBC counting.

Determination of leukocyte counts in cerebrospinal fluid with a disposable plastic hemocytometer

Manual microscopic cell counting in a Fuchs-Rosenthal (FR) chamber has been the gold standard for quantification of leukocytes in cerebrospinal fluid (CSF). However, for accurate determination of the number and differentiation of cells by chamber counting, hemocytometers must be prepared carefully and kept clean. Improper fitting of the chamber and coverslip changes the volume of sample introduced into the chamber well. Moreover, because conventional hemocytometers are used repeatedly and are breakable, there is a risk of exposure to potentially infectious material. To address these issues, disposable plastic hemocytometers have been developed. However, the accuracy, precision, and clinical usefulness of disposable chambers for CSF cells counting have not been determined. In the present study, we evaluated use of a disposable plastic counting chamber (C-Chip DHC-F01) by comparing its performance with that of an FR chamber for counting of CSF specimens and cell suspensions. Within-run precision of C-Chip counting was comparable or superior to that of FR chamber counting, and excellent correlation between cell counts obtained with the C-Chip chamber and FR chamber was observed. However, C-Chip chambers that were kept at 4 degrees C yielded significantly low cell counts. The disposable hemocytometer will reduce the risk of exposure to potentially infectious material. However, use of C-Chip chambers should be avoided in cold environments.

Spurious counts and spurious results on haematology analysers: a review. Part II: white blood cells, red blood cells, haemoglobin, red cell indices and reticulocytes

Haematology analysers provide quick and accurate results in most situations. However, spurious results, related either to platelets (part I of this report) or to other parameters from the cell blood count (CBC) may be observed in several instances. Spuriously low white blood cell (WBC) counts may be observed because of agglutination in the presence of ethylenediamine tetra-acetic acid (EDTA). Cryoglobulins, lipids, insufficiently lysed red blood cells (RBC), erythroblasts and platelet aggregates are common situations increasing WBC counts. In most of these instances flagging and/or an abnormal WBC differential scattergram will alert the operator. Several situations lead to abnormal haemoglobin measurement or to abnormal RBC count, including lipids, agglutinins, cryoglobulins and elevated WBC counts. Mean (red) cell volume (MCV) may be also subject to spurious determination, because of agglutinins, excess of glucose or salts and technological considerations. In turn, abnormality related to one measured parameter will lead to abnormal calculated RBC indices: mean cell haemoglobin content (MCHC) is certainly the most important RBC indices to consider, as it is as important as flags generated by the haematology analysers (HA) in alerting the user to a spurious result. In many circumstances, several of the measured parameters from CBC may be altered, and the discovery of a spurious change on one parameter frequently means that the validity of other parameters should be considered. Sensitive flags now allow the identification of several spurious counts, but only the most sophisticated HA have optimal flagging and more simple HA, especially those without a WBC differential scattergram, do not possess the same sensitivity for detecting anomalous results. Reticulocytes are integrated now into the CBC in many HA, and several situations may lead to abnormal counts.

Portable microscopic cell counter for the determination of residual leucocytes in blood components

BACKGROUND AND OBJECTIVES

The accurate determination of residual white blood cell (WBC) in blood components is of considerable clinical importance, and a variety of methods have been devised for the counting of low levels of residual WBC. In this study, we evaluated the performance of microscopic cell counter with microchannel plastic chip (C-reader) with regard to its ability to quantify WBC in WBC-reduced red cell concentrates.

MATERIALS AND METHODS

In order to quantify residual WBC with the microscopic cell counter, WBC-reduced red cell concentrate was stained using propidium iodide. Three studies were performed: linearity, precision and correlation compared to those of manual Nageotte chamber counting and automatic flow cytometric methods.

RESULTS

Dilution experiments, conducted over a range of 0.7-712 WBC/microl, showed a linearity of r(2) > 0.999, with coefficient of variation values of < or = 15.6% and accuracy of 93.8% over all tested ranges. In comparison with the Nageotte chamber counting and flow cytometric methods, the correlation coefficients were r(2) > 0.995. The detection limit of this method was 0.24 WBC/microl. Total analysis time per sample was approximately 5 min.

CONCLUSION

The microscopic cell counter for residual WBC counting was determined to be efficient at the level of currently defined standards, with acceptable precision and accuracy. This method may prove useful for the quality assurance and control of WBC-depleted blood products.

Neutrophil VCS Parameters Are Superior Indicators for Acute Infection

A reliable and cost-effective laboratory method for diagnosing early bacterial infection is needed. The purpose of this study is to compare the sensitivity and specificity of the mean neutrophil volume (MNV) and neutrophil volume distribution width (NDW) parameters with manual band counts, as well as absolute neutrophil count (ANC) and Creactive protein (CRP). We analyzed the clinical history and laboratory data from 242 adult patients with subsequent randomization into 3 groups: patients with no apparent clinical evidence of infection (group 1), localized infection (group 2), and severe infection (group 3). Total white blood cell counts, percentage of neutrophils, ANC, band counts, MNV, and NDW were progressively elevated from group 1 to group 3. There were good correlations between MNV and ANC (P < .05) or band counts (P < .001). Similarly, the NDW correlated well with ANC (P < .001) and band counts (P < .05). Statistical analyses further confirmed that the MNV and NDW were better parameters, with larger areas under the curve than those of CRP, band count, and ANC. The neutrophil VCS parameters, MNV and NDW, have superior sensitivity and specificity compared to manual band count, ANC, and CRP. MNV and NDW are useful indicators in diagnosing acute infectious processes.

An immunomagnetic single-platform image cytometer for cell enumeration based on antibody specificity

Simplification of cell enumeration technologies is necessary, especially for resource-poor countries, where reliable and affordable enumeration systems are greatly needed. In this paper, an immunomagnetic single-platform image cytometer (SP ICM) for cell enumeration based on antibody specificity is reported. A chamber/magnet assembly was designed such that the immunomagnetically labeled, acridine orange-stained cells in a blood sample moved to the surface of the chamber, where a fluorescent image was captured and analyzed for cell enumeration. The system was evaluated by applying one kind of antibody to count leukocytes and one kind for each leukocyte subpopulation: CD45 for leukocytes, CD3 for T lymphocytes, and CD19 for B lymphocytes. Excellent precision and linearity were achieved. Moreover, these cell counts, each from blood specimens of 42 to 52 randomly selected patients, were compared with those obtained by SP (TruCount) and dual-platform (DP) flow cytometry (FCM) technologies. The cell counts obtained by our system were in between those obtained from the TruCount and DP FCM methods; and good correlations were achieved (R > or = 0.95). For CD4(+) counts, as we expected, the cell count by our system was significantly higher than the CD4(+) T-lymphocyte counts obtained by SP and DP FCM methods. Immunophenotyping of the immunomagnetically selected CD4(+) cells showed that, besides CD4(+) T lymphocytes, a proportion of the CD4(+) dim monocytes was also selected. Our system is a simple immunomagnetic SP ICM, which can potentially be used for enumeration of CD3(+) CD4(+) T lymphocytes in resource-poor countries if an additional CD3 immunofluorescent label is applied.

Microchip-based enumeration of human white blood cells

The advent of flow cytometry has considerably changed the ways in which medical testing is conducted. However, the cost of flow cytometers, their large size, and their maintenance needs make them scarce in resource-poor settings and available almost only in clinical pathology laboratories in developed countries. Because cell enumeration is a basic and crucial support of diagnosis, prognosis, and treatment, an alternative cell-counting method that would potentially be cost-effective, portable, and suitable for use in resource-poor settings is warranted. We describe here a protocol for conducting cell-counting experiments in a simple microfluidic structure. This protocol describes how to build a simple microfluidic cell and perform a total white blood cell (WBC) count through capture and immunolabeling of the WBCs with an anti-CD45 antibody.

Validation of the Beckman Coulter AcT 5 Diff Analyzer in a Reference Laboratory

At the Valle de Hebron Hospital's Central Laboratory, we have performed a study evaluating the performance, reliability, and practicability of the Beckman Coulter AcT 5 analyzer. The results observed with known controls showed within- and between-run imprecision of 1.05% to 6.97% for the basic hemogram parameters. With patient samples, the results were analogous, with within- and between-run imprecision of 1.33% to 5.98%. To complete the evaluation of the AcT 5 counter, we analyzed the influence of possible interfering factors such as the presence of jaundice, lipemia, hemolysis, platelet aggregates, and schistocytes on the results of the automated leukocyte differential as performed by the cell counter with the new chlorazol black stain. We studied the performance of the AcT 5 with regards to ease of use, speed, and cost. Finally, we evaluated the impact of introducing the AcT 5 counter into routine laboratory use as support to resolve problems raised with the Beckman Coulter GenS and LH-750 and the Bayer Advia 120 counters due to samples with interfering factors.

The Application of Beckman Coulter VCS Technology at a Major Cancer Center, with Emphasis on the Detection of Circulating Immature Plasma Cells in Plasma Cell Leukemia

The St. Vincent's Comprehensive Cancer Center (SVCCC) has a large multiple myeloma program in downtown New York City. The laboratory at SVCCC is an integral part of the diagnosing and monitoring of its myeloma patients. Circulating plasma cells are not a common finding in multiple myeloma. Being able to detect plasma cells in peripheral blood is important because they are a prognostic indicator that correlates with disease progression. Furthermore, the peripheral blood plasma cell population can demonstrate morphologic variability. Immature plasma cells, both plasmablasts and proplasmacytes are associated with more aggressive disease and shortened survival. We encountered 3 multiple myeloma patients with circulating immature plasma cells that appeared as distinct populations on our hematology analyzer's automated white blood cell (WBC) differential. The immature plasma cells, given their unique cellular characteristics, appeared in a common place within the WBC differential scatterplot in each patient. In our laboratory, we have utilized this common graphic pattern to screen for immature plasma cells. This pattern has proven to be a useful tool in our large population of multiple myeloma patients. We have also used examination of the scatterplots in other hematologic malignancies such as chronic lymphocytic leukemia. Using this review policy, the laboratory has been able to achieve a smear review of 25% in our highly abnormal patient population.