Sysmex SE-9000 hematology analyzer: performance evaluation on leukocyte differential counts using an NCCLS H20-A protocol. National Committee for Clinical Laboratory Standards

Automated Complete Blood Cell Count Using Sysmex XN-9000® in the Diagnosis of Newborn Infection

The early identification of septically infected newborn infants is important for ensuring good outcomes. Blood cell differentiations are helpful, but they are often time consuming and inaccurate. In this study, we evaluated the use of automatic white blood cell differentiations by flow cytometry for the diagnosis of neonatal sepsis. Episodes of suspected infection in neonates were retrospectively classified into two groups, unlikely infection (UI, levels of Interleukin-6 < 400 pg/mL or CRP within 48 h < 10 mg/L), n = 101 and probable infection (PI, Interleukin-6 ≥ 400 pg/mL or CRP within 48 h ≥ 10 mg/L), n = 98. Complete blood cell counts were performed by Sysmex XN-9000® using flow cytometry. Relative and absolute proportions of immature granulocytes were evaluated. Unexpectedly, the absolute count of immature granulocytes was significantly lower in the group of PI compared to UI neonates. Similar results were found when analysing the relative proportion of immature granulocytes among all neutrophil granulocytes. On the other hand, manually counted immature to total (I/T) ratios of granulocytes were higher in PI than in UI infants. Therefore, we conclude that differentiations of granulocytes by Sysmex XN-9000® can be used to distinguish between infected and uninfected neonates if the results are interpreted according to our findings. A low count of immature granulocytes as determined by Sysmex XN-9000® may indicate neonatal infection.

Diagnostic performance of the variant lymphocyte flag of the Abbott Cell-Dyn 4000 haematology analyser

BACKGROUND

In addition to differential cell counts, modern haematology analysers generate suspect flags if abnormal cells are detected. Reports on validation of suspect flags are scarce. We have routine experience with the Abbott Cell-Dyn 4000 analyser for over 5 years and have previously demonstrated the utility of the blast flag. Here we report a similar study on the performance of the analyser's Variant Lymphocyte (VL) flag.

AIM OF THE STUDY

Evaluation of the diagnostic performance of the Cell-Dyn 4000 VL flag, as compared with lymphocyte morphology in blood smears. In addition, we investigated the usefulness of the numerical VL flag confidence index as provided by the analyser.

MATERIALS AND METHODS

All samples generating a VL flag were reviewed over a 5-month period. We also reviewed smears from patients with known lymphoid disorders, even if the analyser did not flag the sample. Two experienced investigators assessed lymphocyte morphology independently.

RESULTS

In total, 187 samples were included in the study, of which 183 had a VL flag and four had not. Of the 183 flagged samples, 83 appeared to have abnormal lymphocyte morphology and 100, normal lymphocyte morphology. The sensitivity of the VL flag for detecting abnormal lymphocytes was 0.95 and the positive predictive value was 0.44. Using ROC analysis of the VL flag confidence index, the area under the ROC curve was 0.58 (95% confidence interval 0.50-0.65).

CONCLUSIONS

The Cell-Dyn VL flag has reasonable sensitivity but a high false-positive rate. In addition, its performance is insufficient for detecting clinically relevant abnormal lymphocytes. As the VL flag appeared to rely mainly on numerical criteria, it has no added value over numerical criteria defined by the laboratory.

Immature granulocyte detection by the SE-9000 haematology analyser during pregnancy

The objective of this study was to determine the nature of the alarm for immature granulocytes appearing in haemograms from pregnant women, as detected by the immature cell information channel (IMI) of the SE-9000 automated haematology analyser. Of all tests run on pregnant women in a 4-month period (n = 698), the first 100 haemograms with immature granulocyte alarms (14.33%) were collected. Each of these samples was then stained with Wright-Giemsa stain. The following variables were also analysed: age of the mother, trimester and days of gestation, type of delivery, weight and sex of the baby, and Apgar score. Most pregnant women were in the third trimester of gestation (82%) when an alarm was noted on the IMI channel. Of the patients, 62% had normal deliveries. The most frequent complication was obstructed delivery (23%). Mean percentages by microscopic counts of band cells, metamyelocytes, and myelocytes were 2.99, 0.45, and 0.19%, respectively. There was a statistically significant correlation for all cell types between the SE-9000 and the manual count method. No association was observed between the presence of immature granulocytes and the clinical variables analysed. The SE-9000 analyser shows high sensitivity in the IMI channel for detection of immature forms.

The new hematology analyzer Sysmex XE-2100: performance evaluation of a novel white blood cell differential technology

CONTEXT

The new hematology analyzer Sysmex XE-2100 (TOA Medical Electronics, Kobe, Japan) has a novel, combined, white blood cell differential technology and a special reagent system to enumerate nucleated red blood cells.

DESIGN

Performance evaluation of both technologies of the Sysmex XE-2100 according to the H20-A protocol of the National Committee for Clinical and Laboratory Standards and comparison of the results with those for the hematology analyzer Sysmex NE-8000 (TOA Medical Electronics).

SPECIMENS

Five hundred forty-four blood samples randomly chosen from various inpatient and outpatient departments of the Vienna University hospital.

RESULTS

Five-part white blood cell differential counts on the XE-2100 revealed excellent correlation with the manual reference method for neutrophils, lymphocytes, and eosinophils (r =.925,.922, and.877, respectively) and good correlation for monocytes and basophils (r =.756 and.763, respectively). The efficiency rates of flagging for the presence of >/=1% abnormal white blood cells were 83% (XE-2100) and 66% (NE-8000). The correlation of automated and microscopic nucleated red blood cell counts was excellent (r =.97).

CONCLUSIONS

From the present evaluation and our former experience with other types of Sysmex analyzers, we conclude that the new white blood cell differential technology of the XE-2100 represents a further development toward more efficient flagging of abnormal white blood cells.

Flow cytometric reticulocyte counting. Parallel evaluation of five fully automated analyzers: an NCCLS-ICSH approach

We performed a parallel evaluation of 5 automated reticulocyte analyzers. The guidelines were those proposed by the National Committee for Clinical Laboratory Standards and the International Council for Standardisation in Haematology. Duplicate analyses were performed for 225 healthy subjects and 115 patients affected by various diseases. The reference intervals were different for each method (ADVIA 120, 27-125 x 10(3)/microL [27-125 x 10(9)/L]; CELL DYN 4000, 25-108 x 10(3)/microL [25-108 x 10(9)/L]; GEN-S, 20-85 x 10(3)/microL [20-85 x 10(9)/L]; SE 9500 RET, 23-95 x 10(3)/microL [23-95 x 10(9)/L]; and VEGA RETIC, 30-130 x 10(3)/microL [30-130 x 10(9)/L]). The comparisons of percentage counts with the microscopic reference method were satisfactory for all automated methods. However, a tendency to overestimate at low counts was noted. This progressively increased from the SE 9500 RET to the VEGA RETIC. The imprecision was excellent for all the methods at normal and high concentrations. This was higher at low concentrations. When compared with the microscopic reference, the analyzers showed satisfactory sensitivity at low counts and excellent sensitivity at high counts. The overall agreement varied from 74.8% for the GEN-S to 86.1% for the SE 9500 RET.

Cytofluorometric methods for assessing absolute numbers of cell subsets in blood. European Working Group on Clinical Cell Analysis

The enumeration of absolute levels of cells and their subsets in clinical samples is of primary importance in human immunodeficiency virus (HIV)+ individuals (CD4+ T- lymphocyte enumeration), in patients who are candidates for autotransplantation (CD34+ hematopoietic progenitor cells), and in evaluating leukoreduced blood products (residual white blood cells). These measurements share a number of technical options, namely, single- or multiple-color cell staining and logical gating strategies. These can be accomplished using single- or dual-platform counting technologies employing cytometric methods. Dual-platform counting technologies couple the percentage of positive cell subsets obtained by cytometry and the absolute cell count obtained by automated hematology analyzers to derive the absolute value of such subsets. Despite having many conceptual and technical limitations, this approach is traditionally considered as the reference method for absolute cell count enumeration. As a result, the development of single-platform technologies has recently attracted attention with several different technical approaches now being readily available. These single-platform approaches have less sources of variability. A number of reports clearly demonstrate that they provide better coefficients of variation (CVs) in multicenter studies and a lower chance to generate aberrant results. These methods are therefore candidates for the new gold standard for absolute cell assessments. The currently available technical options are discussed in this review together with the results of some cross-comparative studies. Each analytical system has its own specific requirements as far as the dispensing precision steps are concerned. The importance of precision reverse pipetting is emphasized. Issues still under development include the establishment of the critical error ranges, which are different in each test setting, and the applicability of simplified low-cost techniques to be used in countries with limited resources.