Laboratory evaluation of the Sysmex SE‐9500 automated haematology analyser

The Sysmex SE‐9c500 is a new, fully automated haematology analyser, providing a complete blood count (CBC), including a five‐part differential count (DC), with flagging of morphological abnormalities. The SE‐9500 was evaluated according to guidelines published by the International Committee for Standardisation in Haematology (ICSH). The results demonstrated minimal carryover (< 0.01%) and excellent linearity for WBC, RBC, HGB and platelet (PLT) (r > 0.995). Samples were stable with regard to CBC parameters after storage for up to 48 h at room temperature (RT) and 4 °C. Imprecision was generally acceptable for all CBC parameters (CV < 5%). Correlation between the SE‐9500 and reference methods was excellent (r > 0.97) for all the major CBC parameters (WBC, RBC, HGB, PLT). There was minimal interference for WBC, RBC, HGB and PLT at high concentrations of bilirubin (BIL=224 μmol/l) or triglyceride (TG=7.78 mmol/l). SE‐9500 reference values for CBC parameters are presented. Our results indicate that the SE‐9500 is an excellent tool for routine haematological examination.     

Performance evaluation of the Sysmex XS-1000i automated haematology analyser

The Sysmex XS-1000i is a compact new, fully automated haematology analyser, designed to generate complete blood counts with five-part leucocyte differential. In our study, a Sysmex XS-1000i instrument was evaluated according to Clinical Laboratory Standards Institute (CLSI) and International Council for Standardization in Haematology (ICSH) guidelines. Precision, carry-over and linearity were determined. Using a total of 700 patient samples, results from the Sysmex XS-1000i were compared with those from a Sysmex XE-2100, an Abbott Cell Dyn 4000 and the manual reference leucocyte differential. Using quality control material, total and within-run imprecision was less than 3% except for platelets. The system demonstrated good linearity over the entire reporting range and no carry-over (<0.5%). The Sysmex XS-1000i showed good correlation with XE-2100, CD-4000 and the manual reference leucocyte differential. Overall flagging sensitivity and specificity were 91% and 48%, respectively. In conclusion, the Sysmex XS-1000i demonstrated good analytical performance, is able to generate a complete blood count with five-part differential on low blood volumes and has considerable back-up capacity.     

An evaluation of the CELL-DYN 1700® haematology analyser: automated cell counting and three-part leucocyte differentiation

The performance of the CELL-DYN 1700® (Abbott Diagnostics, Abbott Park, IL, USA) was evaluated in a tertiary care hospital laboratory using the guidelines proposed by the German Society of Clinical Chemistry. Precision, accuracy, linearity, background counts, and carry-over were satisfactory for all measured standard parameters including haemoglobin concentration, haematocrit, red blood cell count, mean corpuscular volume (MCV), red cell distribution width (RDW), white blood cell count and platelet count. With 259 selected normal and abnormal blood samples the results of the CELL-DYN 1700® (CD1700) compared very well (r > 0.96 for all parameters with exception of RDW) with those obtained with the Bayer Diagnostic H-1 and the Hoffmann-La Roche Cobas Argos systems. This study considered in particular the performance of the CD1700 three-part leucocyte differential. For those samples without instrument-generated suspect flags, the neutrophil and lymphocyte percentages were highly correlated with the results of the H-1 blood cell counter (r = 0.97 and 0.98, respectively) and with manual 400-cell differentials (r = 0.91 and 0.88, respectively). In contrast, the CD1700 mid-fraction which comprised the composite total of mono cytes, eosinophils, basophils and precursor white cells (when present) could not be directly compared to the differentials from the H-1 system or from manual microscopy. For those samples with CD1700 instrument suspect flags, the neutrophil and lymphocyte differential results also compared well with both the H-1 (r = 0.93 and 0.93, respectively) and manual estimates (r = 0.89 and 0.87, respectively). In conclusion, the CD1700 is an accurate haematology analyser for cellular blood counts and three-part leucocyte differentiation.     

Automated reticulocyte counting: evaluation of the Coulter® STKS Haematology Analyser reticulocyte counting function

This study evaluated reticulocyte counting with the automated reticulocyte function of the Coulter STKS Haematology Analyser. This is an upgrade option for Coulter STKS and MAXIM haematology analysers. Reticulocyte counts obtained with the automated reticulocyte counting function were compared with those obtained by visual counting. Reticulocyte counting with both methods gave excellent comparability with a correlation coefficient of 0.98. Results were consistent with the well documented imprecision of the manual method with a coefficient of variation (CV) of 16–22%. In contrast, the automated reticulocyte counting function was more precise with a CV of 12.3%. In both cases, counts were stable after storage for 24 h at room temperature and 4 °C. Our results suggest that the use of this upgrade will be beneficial for many laboratories.     

Performance evaluation of the Abbott CELL‐DYN Ruby and the Sysmex XT‐2000i haematology analysers

Two mid‐range haematology analysers (Abbott CELL‐DYN Ruby and Sysmex XT‐2000i) were evaluated to determine their analytical performance and workflow efficiency in the haematology laboratory. In total 418 samples were processed for determining equivalence of complete blood count (CBC) measurements, and 100 for reticulocyte comparison. Blood smears served for assessing the agreement of the differential counts. Inter‐instrument agreement for most parameters was good although small numbers of discrepancies were observed. Systematic biases were found for mean cell volume, reticulocytes, platelets and mean platelet volume. CELL‐DYN Ruby WBC differentials were obtained with all samples while the XT‐2000i suppressed differentials partially or completely in 13 samples (3.1%). WBC subpopulation counts were otherwise in good agreement with no major outliers. Following first‐pass CBC/differential analysis, 88 (21%) of XT‐2000i samples required further analyser processing compared to 18 (4.3%) for the CELL‐DYN Ruby. Smear referrals for suspected WBC/nucleated red blood cells and platelet abnormalities were indicated for 106 (25.4%) and 95 (22.7%) of the XT‐2000i and CELL‐DYN Ruby samples respectively. Flagging efficiencies for both analysers were found to be similar. The Sysmex XT‐2000i and Abbott CELL‐DYN Ruby analysers have broadly comparable analytical performance, but the CELL‐DYN Ruby showed superior first‐pass efficiency.     

Automated reticulocyte counting using the Sysmex RAM‐1

Reticulocyte counting using the Sysmex RAM‐1 was evaluated. The results of 113 samples analysed on the Sysmex RAM‐1 were compared with those from both flow cytometry (FCM) and a manual technique. Reticulocyte counting with the Sysmex RAM‐1 showed excellent precision, with an overall coefficient of variance (CV) less than 5%, and almost no carry‐over. Reticulocyte counts were stable after blood storage for 48 h at 4°C and room temperature (RT). Linearity was demonstrated very well for Sysmex RAM‐1 and FCM (r_RAM=0.9998, r_FCM=0.9974, P < 0.001) when reticulocyte counts were 5 × 10⁹/l–480 × 10⁹/l. Comparisons of methods showed a good relation for reticulocyte counts between Sysmex RAM‐1 and manual counting (r=0.9760), FCM and manual counting (r=0.9623), and Sysmex RAM‐1 and FCM (r=0.9527). Analysis of receiver operating characteristic curves showed that the true‐positive rate (TPR) was 0.95 for Sysmex RAM‐1, and 0.83 for FCM; the area under curve was 0.999 and 0.972 for Sysmex RAM‐1, 0.990 and 0.900 for FCM. These findings confirm that Sysmex RAM‐1 can make counting reticulocytes easier, more accurate and more reproducible.     

Evaluation of the Roche Cobas Argos 5Diff automated haematology analyser with comparison to a Coulter STKS

Summary. The performance of the Roche Cobas Argos 5Diff (Argos) automated haematology analyser was evaluated by comparison to manual blood film examination and a Coulter STKS (STKS) analyser. The Argos demonstrated excellent between and inter-batch imprecision for all parameters, except the MCHC, and good linearity for Hb, WBC and platelet count (PLT). After an initial fall the PLT, results were stable for up to six h at 18°C in EDTA(K3) after which an increasing proportion of cells were classified as lymphocytes. Results of 239 patient samples analysed on both instruments, compared by linear regression, gave excellent correlation (r² > 0.90) for most parameters with the exceptions of the MCHC (0.317), eosinophils% (0.756), monocytes% (0.48) and basophils% (0.002).‘Flagging’of cellular abnormalities by the Argos resulted in excellent sensitivity (97.5%), specificity (93.2%) and efficiency/agreement (93.2%), with fewer false positive and negative results than the STKS, although these differences were not statistically significant. The performance characteristics of the Argos were comparable to those of the STKS with a possible improvement in its flagging abilities.     

Development and clinical application of nucleated red blood cell counting and staging on the automated haematology analyser XE‐2100TM

We initially developed a new flow cytometric (FCM) reference method for the enumeration and staging of nucleated red blood cells (NRBC) in 1997 [ Wang et al., 1998 (XIth International Symposium on Technological Innovations in Laboratory Haematology, Banff, Canada, 1998); Tsuji et al., 1999 (Cytometry, 1999)]. The method used CD45 antibody and propidium iodide staining to separate NRBCs from other cells. Accuracy and precision were enhanced because larger numbers of cells were counted than was possible with the manual method. We also developed a method for automated NRBC counting on a haematology analyser, the XE‐2100 (Wang, 1988). NRBC were separated from other cells using a special lysing buffer and a fluorescent dye. The XE‐2100 was found to detect peripheral and cord blood NRBC accurately and precisely when compared with cell morphology or FCM control methods. The FCM NRBC staging method was established through the identification of different NRBC populations following the novel staining and lysing method. To evaluate the method further, we sorted samples containing NRBCs using a FACSort and investigated NRBC staging on the Sysmex XE‐2100^TM based on the cell sorting results. Data were analysed using special software (ida ). First, we used the data in various parameter combinations. We then established gates to classify the NRBC populations. Finally, we analysed blood specimens from patients with different types of diseases to explore possible clinical applications.     

Comparison of materials for quality control of platelet counting using the Coulter Model S Plus

This paper describes the preparation and use of a control material (PlasCon) which may be aspirated in prediluted form to monitor the calibration of the Coulter Counter Model S Plus. A comparison study with two commercial preparations, and a study of the stability and between-batch reproducibility of PlasCon, show the material to be suitable for quality control of platelet counting.     

Two-centre evaluation of the Abbott CD3500 blood counter

Summary The CD3500 blood counter (Abbott Laboratories) is a 33 parameter fully automated blood counter that produces a five part differential count with flagging of leucocyte abnormalities. In this evaluation excellent correlation between CD3500 and Coulter STKR blood counter was found for all red cell and platelet parameters on the 221 samples tested. Studies of carryover, mixing efficiency and precision also gave excellent results. There was a good correlation with manual 400 cell differential counts for neutrophils, lymphocytes, monocytes and eosinophils for the 468 samples compared. Correlation of CD3500 and manual basophil counts was poor. Normal samples stored at 4°C and analysed while cold showed satisfactory stability for WBC, RBC, Hb, MCV and platelets for 48 h and a stable differential for 24 h. Correlation with the differential count produced by the Coulter STKS showed good correlation for neutrophils, lymphocytes, monocytes and eosinophils; correlation with STKS basophils was poor. False positive flagging rate varied between 8.9% (Band and/or IG) and 0.9% (NRBC) depending on the nature of the flag; 5.8% of samples exhibited two or more false positive flags. No significant breakdowns were encountered during the period of the evaluation. The scatterplot displays of laser light scatter produced by the instrument provide an interesting adjunct to conventional morphology.     

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

Summary. 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 I1 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.     

Spurious counts and spurious results on haematology analysers: a review. Part I: platelets

The widespread use of haematology analysers (HA) has led to a major improvement of cellular haematology, because of quick and accurate results found in most instances. However, in several situations, spurious results are observed. Inadequate blood samples, situations induced by the anticoagulant(s) used, peculiar changes related to the pathology in the patient, and technical considerations about performances of the various HA must be considered. Spurious thrombocytopenia occurs in several circumstances related to the presence of ethylenediamine tetra-acetic acid (EDTA) used as the anticoagulant. Mechanism of EDTA-dependent platelet (PLT) agglutination is related to circulating (auto)antibodies directed against normally hidden epitope(s) in the glycoprotein alpha IIb/beta IIIa complex from PLT membrane exposed only in the presence of EDTA. Other spuriously low PLT counts may be related to EDTA, including PLT rosetting around white blood cells (WBC; satellitism) and PLT-WBC aggregates, but mechanisms responsible for those latter phenomena are less well known. Spurious increase of PLT count may be related to several situations, including fragmented red blood cells, cytoplasmic fragments of nucleated cells, cryoglobulins, bacteria or fungi, and lipids. Flags generated in several of these situations alert the operator on possible abnormal findings and may identify the problem. Analysing only PLT parameters is not sufficient: in many situations the WBC differential scattergram is of crucial help for flagging. Flags generated depend on the software version on the HA used, the performance in detecting the same anomalies may differ according to which analyser is used, even those from the same manufacturer. Operators must be aware of the characteristics of their analyser and be able to recognize and circumvent anomalous results.     

Effects of bacteria and yeast on WBC counting in three automated hematology counters

Bacteria or yeast may be observed on peripheral blood smears and may lead to spuriously elevated platelet counts. They have been reported to disturb the white blood cell (WBC) differential count if they clumped together, and a large number of such microorganisms have been shown to increase WBC counts. The purpose of this study was to evaluate the spurious rise in WBC counts according to species of microorganisms and automated hematology analyzers. The species we selected were Staphylococcus aureus, Escherichia coli, Candida albicans, C. tropicalis, C. krusei, C. dubliniensis, C. glabrata, and C. parapsilosis. We investigated the effects of bacteria and yeast on peripheral blood samples by the ADVIA 120/2120 Hematology System, Sysmex XE-2100 (TOA Medical Electronics, Kobe, Japan) and Coulter LH 750 (Beckman Coulter, Miami, FL, USA). C. albicans, C. tropicalis, C. krusei, and C. dubliniensis had an overt effect on the WBC count at concentrations of up to 1–5 × 10⁷ colony-forming units (CFU)/mL in three automated cell counters, and C. glabrata and C. parapsilosis, when present at concentrations of 1–5 × 10⁸ CFU/mL, caused a significant increase in the WBC count obtained by the Sysmex XE-2100 but not by the ADVIA 120/2120 system and Coulter LH 750 (p < 0.05). In conclusion, yeast may influence the results of peripheral blood smears only when the yeast concentration is unusually high. The results differed among analyzers and among species of yeast. Hematologists should be aware that samples containing bacteria and yeast may give erroneously high WBC counts and differential leukocyte counts and should review the peripheral blood smear by microscopy.     

Factors producing error in the total leucocyte count as measured on the Coulter Counter S Plus IVD

Summary Whole blood specimens, anticoagulated with potassium EDTA, which were seen to have particles interfering with the total leucocyte count were collected. This interference was detected, when the samples were processed through a Coulter Counter S Plus IVD, by R1 regional flags or backlighting of the leucocyte count. These specimens then had visual leucocyte counts performed using a counting chamber method and were examined microscopically, to ascertain possible causes of the interference. It was shown that the degree of error in the leucocyte count produced varies considerably but can be very high. Particles causing the error were found to include fibrin strands, platelet clumps, nucleated red cells and giant platelets.     

Performance evaluation of the Celltac F haematology analyser

Introduction: Performance of the Celltac F haematology analyser (MEK‐8222) which provides 22 parameters, including a 5‐part differential, was compared with the Sysmex XE‐2100. Methods: 242 EDTA samples were investigated. Differential results from both instruments were compared with the reference microscopic count. Flagging performance was compared with cell morphology seen in the blood films. Results: Precision met or exceeded manufacturer’s specifications, carryover was minimal (≤1.37%) and linearity was excellent (R ≥ 0.99). Results were stable for at least 8 h at room temperature and for 24 h at 4 °C. Comparisons were excellent for white blood cells, red cell count, Hb, HCT and platelets (R ≥ 0.98). All other red cell and platelet parameters showed good correlation with the XE‐2100 (R ≥ 0.93) except for mean cell haemoglobin concentration. The differential was comparable to the XE‐2100 for neutrophils, lymphocytes and eosinophils and acceptable for monocytes. Correlation of automated differentials with manual reference counts and the efficiency of flagging of blasts, immature granulocytes and platelet clumps were similar for both instruments. Celltac F demonstrated better efficiency for atypical lymphocyte and platelet clumps. Conclusion: The Celltac F shows broadly comparable analytical performance to the XE‐2100 for the parameters assessed. The Celltac F is recommendable for medium‐sized laboratories or as a back‐up instrument in larger laboratories.     

Evaluation of a semi-automated reticulocyte counting method using the Coulter® STKS-2A blood cell counter

Summary Reticulocyte counting was assessed on the Coulter® STKS-2A automated blood cell counter. Using a two step procedure, blood samples were first incubated with the supravital stain new methylene blue. An acidic reagent was then added to clear the haemoglobin and any stained RNA was preserved within the cell. The cells were then analysed by measurement of volume, conductivity and light scatter (VCS). The results of 123 samples analysed on the STKS-2A were compared with those from a Toa Sysmex R-1000 reticulocyte counter. One hundred and seven samples gave no review flags and reticulocyte counts ranging from 0.5% to 22.8%, resulting in a correlation coefficient of 0.93 for the methods. Between run imprecision studies gave CVs ranging from 5.3% for a reticulocyte count of 8.7% to a CV of 16.3% for a 0.34% count. Stability studies showed insignificant changes over 72 h storage. These findings confirm that VCS technology can be adapted to provide precise and accurate routine reticulocyte analysis.     

联合检测在小儿肺炎诊断中的意义

目的探讨联合检测降钙素原(PCT)、C-反应蛋白(CRP)、白细胞计数(WBC)包括中性粒细胞分类计数(NC)在小儿肺炎诊断中的实用价值。方法选取57例肺炎患儿(细菌性肺炎30例、病毒性肺炎27例)和31例健康对照儿童进行PCT、CRP、WBC和NC检测,并将三组数据进行统计分析。结果细菌性肺炎组PCT、CRP、WBC和NC结果与病毒性肺炎组、健康对照组进行比较均有统计学差异(P均0.05)。病毒性肺炎组与健康对照组比较,PCT、CRP、NC均有统计学差异(P均0.05),而WBC比较无统计学差异(P0.05)。细菌性肺炎组四项指标阳性率明显高于病毒性肺炎组(P0.01)。结论 PCT对细菌性与病毒性肺炎有早期鉴别诊断价值,具有较高的灵敏性和特异性。联合检测PCT、CRP、WBC、NC的变化有助于鉴别患儿病原体类型。