The new haematology analyzer DxH 800: an evaluation of the analytical performances and leucocyte flags,comparison with the LH 755

Introduction: The analytical performance and the abnormality messages on differential (flags) of the new analyzer Beckman Coulter DxH 800 were compared with those of the LH 755. Methods: First, we evaluated the accuracy of the results of the DxH 800, in comparison with the LH 755, in 125 samples without alarm using unflagged sample results on both analyzers. Second, flagged samples on the LH 755 but not flagged by the DxH 800 were evaluated by flow cytometry for accuracy of the DxH 800 results. Finally, we evaluated the sensitivity and specificity of abnormality messages on differential given by the analyzers, in comparison with manual blood smears. Results: The correlation coefficients (R) for complete blood count parameters and differential demonstrated that the DxH 800 results were similar to that of LH 755. Excellent correlation coefficients between DxH 800 and flow cytometry results were found for white blood cell count (R = 0.985, n = 31), platelet count (R = 0.976, n = 51) and nucleated red blood cells (R = 0.966, n = 37). The overall performance showed an increased sensitivity (0.892) and specificity (0.864) of the flags on DxH 800 when compared to the LH 755 (0.846 and 0.733, respectively). Conclusion: The DxH 800 provides reliable results and increases laboratory efficiency by reducing working time and costs associated with the optical validation of the results.     

Coulter LH750血细胞分析仪检测网织红细胞计数性能及其应用价值评价

目的评价Coulter LH750血细胞分析仪检测网织红细胞(reticulocyte,Ret)的性能及其在临床的应用价值。方法应用Coulter LH750血细胞分析仪测定随机抽样的160例Ret检测标本,并与手工法进行比较。结果 Coulter LH750血细胞分析仪(仪器法)检测160例标本所得的Ret值与手工法(显微镜目测法)呈正相关(r=0.997),且结果差异无统计学意义(P0.05)。结论 Coulter LH750血细胞分析仪检测Ret具有重复性好、精密度及准确性高、操作简便快捷、检测速度快等优点,可提供较多的Ret相关参数,标本不需特别处理,值得广泛推广应用。     

Performance evaluation and relevance of the CellaVision DM96 system in routine analysis and in patients with malignant hematological diseases

The CellaVisiontrade mark DM96 is an automated image analysis system dedicated to locating and preclassifying the various types of white blood cells in peripheral blood smears. The system also partially characterizes of the red blood cell morphology and is able to perform platelet counts. We routinely analyzed the blood samples from 440 patients with quantitative and/or qualitative abnormalities detected by the XE-2100 Sysmextrade mark. Only 2.6% of cells are not identified by DM96trade mark. After classification of the unidentified cells very good correlation coefficients are observed between DM96trade mark and manual microscopy for most hematological parameters and accuracy is judged excellent up to 98%. For most common parameters, false positive and false negative ratios are also very good. Whatever the pathology and the number of blasts on smear, all patients were positive for blast detection on DM96trade mark. The system is a useful tool for assisting in the diagnosis and classification of most acute or chronic leukemia. Automatic cell location and preclassification, along with unique cell views on the computer screen, could reduce the time spent performing differentials and make real-time collaboration between colleagues a natural part of the classification process. The workstation also provides an ergonomically correct and relaxed working environment. We suggest its use in routine analysis; the system could be very helpful for the accurate morphological diagnosis of samples from patients with malignant hematological disease.     

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.     

Evaluation of cell population data on the UniCel DxH 800 Coulter Cellular Analysis system as a screening for viral infection in children

Introduction: The utility of WBC cell population data (CPD) for the differential diagnosis of viral infection from normal control, bacterial infection, and tuberculosis in children was investigated. Methods: A data set of 602 total whole‐blood samples were analyzed on the DxH 800 System for complete blood cell count (CBC) with leukocyte differential from children with the following sample breakdown: 77 confirmed diagnoses of viral infections (Epstein–Barr virus; 30, influenza A; 19, rota virus; 11, other viruses;17), 54 normal control, 71 bacterial infection, 17 TB patients, and 383 with various diseases. The mean (MN) and standard deviation (SD) of the volume (V), conductivity (C), five light‐scatter measurements, and 14 calculated parameters were obtained for the leukocytes. Results: Using a combination of the CBC and CPD parameter values, a decision rule, composed of 21 parameters, for the screening of viral infection in children was developed. Using this decision rule, 74 of 77 (96.1%) viral infections, two of 54 (3.7%) normal samples, one of 17 (5.9%) TB, and six of 71 (8.5%) bacterial infection samples were identified. The sensitivity was 96.1%, and specificity for normal control was 96.3% with an overall specificity of 93.7%. Fifty‐nine samples of 383 samples (15.4%) collected from in‐patient children with various diseases without confirmation of viral infection were included in this decision rule. Conclusion: In conclusion, the implementation of leukocytes CPD parameters can be useful in the detection of viral infection in children.     

Transfusion of platelet concentrates – clinical evaluation of two preparations

Abstract: The aim of this study was to compare the clinical effect of transfusion of platelet concentrates (PC) prepared from pooled buffy coats (BC) and PCs collected from a single donor (SD) by an apheresis technique. The influence of storage time and various clinical conditions was also studied. Thirty-two patients suffering from haematological malignancies were given a total of 326 platelet concentrates; 180 BC-PCs and 146 SD-PCs, median 7 transfusions per patient. BC-PCs contained 312±52×10⁹ and SD-PCs 383 ± 133 × 10⁹ platelets/unit (mean ± SD). The mean storage time of BC-PC was 3 d and that of SD-PC 1 d. The mean platelet count of the patients before transfusion was 11 ± 8 ×10⁹/L. Regression analysis showed a significant decrease of the post-transfusion platelet corrected count increment (CCI) during storage of PCs for 1–5 d (BC-PC: p <0.01; SD-PC: p <0.05). There was no difference in platelet increment between BC-PC and SD-PC. Human leukocyte antigen (HLA) alloimmunization was the major cause of clinical refractoriness to random donor platelet transfusions but splenomegaly also caused low CCI values.     

Evaluation and use of the white blood cell differential provided by the Coulter® STKS in a children's hospital

Summary. The Coulter® STKS was evaluated in a children's hospital, in order to (a) compare the WBC differential given by the instrument to a 400 cell visual differential (reference method); (b) evaluate the sensitivity and specificity of the alarm system, and (c) provide data concerning the use and interpretation of results in children. 653 blood samples were collected. The Coulter® STKS results were studied in 523 patients having no morphological abnormalities in the blood smears, separated into subgroups according to the presence of STKS alarms and according to age. The results were found accurate both in STKS negative and STKS positive patients (i.e., those with alarms:‘Blasts', Imm Gran 2, Variant Lymph, NRBC, review slide). Negative STKS results had the same accuracy in all age groups, except in neonates where slide review must be systematically performed. The instrument exhibited a good sensitivity of the suspect flags studied (91.4%), with a lower specificity (72%) reflecting the number of false positive results found in our group, probably due to the cytological features particular to children. However, it was shown that the numerical results given by the Coulter® STKS in positive patients could be taken into account, provided that a scan of the blood smear was negative for morphological WBC abnormalities.     

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.     

Flow cytometric analysis of platelet activation under calcium ion‐chelating conditions

Platelet activation and aggregation results in factitious counting and sizing in routine haematology testing. In this study, the possibility of platelet activation in anticoagulated solutions was examined. Whole blood was examined using an automated counter and a flow cytometer before and after strong vortex agitation. Blood treated with ethylenediaminetetraacetic acid (EDTA) exhibited platelet activation both pre‐ and postagitation but activated platelets did not cause platelet aggregation. With sodium citrate, platelets were only minimally activated both pre‐ and postagitation. Heparin‐treated blood exhibited minimal platelet activation preagitation, but agitation resulted in strong platelet activation and aggregation. Platelet size was increased by agitation in blood with EDTA and with sodium citrate, in association with significant increases in mean platelet volume (MPV) and platelet distribution width (PDW), but MPV and PDW were significantly higher in EDTA solution than in sodium citrate solution. Change in platelet size was observed even in the presence of EDTA, indicating that careful sampling and processing are needed in the collection of specimens. Specimens obtained from patients with EDTA‐dependent pseudothrombocytopenia exhibited the same level of activation as controls, although platelets exhibited aggregation in such specimens. In conclusion, platelet activation involving platelet size change can occur in the absence of calcium ions in blood treated with EDTA.