ISLH

Laboratory Hematology 6:83-92 © 2000 Carden Jennings Publishing Co., Ltd.

Official Publication

Performance Evaluation of the Sysmex XE-2100 Hematology Analyzer JERELYN WALTERS,1 PATRICIA GARRITY2 1

ACL Laboratories, West Allis; 2Milwaukee Area Technical College, Milwaukee, Wisconsin

ABSTRACT

(NRBC) count. Differential parameters, reticulocyte analysis, and NRBC counts are determined using the principles of flow cytometry with a semiconductor laser and appropriate fluorescent dyes. Instrument throughput is 150 samples per hour for the full hemogram, 5-part differential, and NRBC count. The bidirectional interface capability with the laboratory information system allows for sample-to-sample discrete testing. The aim of this study was to evaluate the performance of the Sysmex XE-2100 and assess its capability as an integrated hematology analyzer. The parameters evaluated for accuracy, precision, carryover, linearity, and stability were as follows: hemoglobin (HGB), hematocrit (HCT), red blood cells (RBCs), white blood cells (WBCs), 5-part automated differential, and impedance platelet count (PLT-I). The routine blood cell count parameters were compared with the SE-9000 (Sysmex). Differential performance was evaluated according to the National Committee for Clinical Laboratory Standards (NCCLS) document H20-A 1 [1]. The NRBC parameter was evaluated to assess accuracy, precision, and linearity. This study was performed in the core laboratory of a large health care system. Examination of the Sysmex XE 2100 reticulocyte parameters and optical platelet count (PLT-O) was performed in a separate study, and the results are not reported here.

A new hematology analyzer, the XE-2100 (Sysmex, Kobe, Japan), was evaluated for performance in the core laboratory of a multiple-hospital system. Complete blood count performance was evaluated in comparison to the SE-9000 (Sysmex). Differential performance was evaluated according to the National Committee for Clinical Laboratory Standards (NCCLS) document H20-A 1. Precision, carryover, correlation, and linearity studies all showed excellent results. Stability studies showed no significant change in differential parameters for a period of 68 hours at both refrigerated and room temperatures. It appears that the stability of the automated differential on the XE-2100 now exceeds the stability of red blood cell size parameters that were stable for 36 hours when refrigerated. Results comparing the XE-2100 automated differential with the 400-cell manual differential were very good. The new nucleated red blood cell (NRBC) measurement showed excellent precision and linearity. Correlation with manually enumerated NRBCs exceeded acceptable statistical standards. The evaluation led to the conclusion that the XE-2100 is an accurate and precise high-speed analyzer. Lab Hematol. 2000;6:83-92.

KEY WORDS:

Automation · Hematology · Sysmex XE-2100 analyzer · White blood cell differential

MATERIALS AND METHODS Instruments The Sysmex XE-2100 is an integrated multiparameter hematology analyzer with the capacity to store analysis data plus histograms for 10,000 samples using a Windows NT–based platform. An example of the Sysmex XE-2100 histogram/scattergram and data analysis printout can be seen in Figure 1. There are 11 quality control files available for use. This analyzer also incorporates a system of flags to alert the operator to the presence of the following: atypical lymphocytes; abnormal lymphocyte/L-blasts; left shift; immature granulocytes; blasts; NRBCs; RBC fragments; RBC lyse resistance; RBC agglutination; dimorphic population; turbidity/hemoglobin interference; iron deficiency; HGB defects; platelet clumps; WBC, NRBC, reticulocyte, and platelet (PLT) abnormal scattergrams; and RBC and PLT abnormal

INTRODUCTION The Sysmex XE-2100 (Sysmex, Kobe, Japan) is a new discrete hematology analyzer designed for high-volume testing in clinical laboratories. The analyzer provides a 14-parameter hemogram as well as a 5-part differential, integral reticulocyte analysis including immature reticulocyte fraction, and a nucleated red blood cell

Correspondence and reprint requests: Jerelyn Walters, 11026 W. Godsell, Milwaukee, WI 53130 (e-mail: [email protected]) (Received March 9, 2000; accepted May 10, 2000)

83

84

J.Walters and P. Garrity

Negative

FIGURE 1. Sysmex XE-2100 histogram/scattergram and data analysis printout. SFL indicates side fluorescent; SSC, side scatter; FSC, forward scatter; RF, radio frequency; DC, direct current; WBC, white blood cell; BASO, basophil; IMI, immature myeloid information; NRBC, nucleated red blood cell; RET, reticulocyte; PLT-O, optical platelet count; RBC, red blood cell; PLT, platelet; HGB, hemoglobin; HCT, hematocrit; MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; RDW-SD, red blood cell distribution width by standard deviation; RDW-CV, red blood cell distribution width by coefficient of variation; MPV, mean platelet volume; NEUT, neutrophil; LYMPH, lymphocyte; MONO, monocyte; EO, eosinophil; IRF, immature reticulocyte fraction; IP, interpretive.

distribution. User-defined flags can be set to identify abnormal numerical results. An example of the Sysmex XE-2100 histogram/scattergram and data analysis printout for an abnormal sample can be seen in Figure 2. HGB determination is achieved using the sodium lauryl sulfate (SLS)-hemoglobin method; SLS is a cyanide-free reagent.

RBCs and PLT-I are enumerated in the RBC/PLT channel using the sheath flow direct current (DC) detection method [2]. HCT is simultaneously determined using the RBC pulse height detection method [3]. The total and differential WBC counts are determined by flow cytometry, and each cell is analyzed by 3 different dispersion

Sysmex XE-2100 Performance Evaluation

WBC IP Message(s) Neutrophilia Monocytosis Leukocytosis NRBC Present

RBC/RET P Message(s) RET Abn Scattergram Reticulocytosis Anisocytosis Macrocytosis

85

PLT IP Message(s) PLT Abnormal Distribution

Immature Gran? Left Shift? FIGURE 2. Sysmex XE-2100 histogram/scattergram and data analysis printout: abnormal sample. Diff. Morph. indicates differential morphology. For other definitions, see legend to Figure 1.

angles: forward-scattered light, lateral-scattered light, and lateral fluorescent light. The immature myeloid information (IMI) is a separate channel that provides additional WBC information on the presence of immature granulocytes, blasts, and hematopoietic progenitor cells. This channel uses a hemolytic reagent that selectively protects immature cells that are analyzed by the radio frequency (RF)/DC detection method [4]. Nucleated RBCs are detected in a separate flow channel using both a specific lysing reagent and a fluorescent dye.

Reticulocytes are enumerated by flow cytometry using a semiconductor laser and a nucleic acid fluorescent dye. The dye reaction is based on the same principle as that of the Sysmex R series reticulocyte analyzers [5]. By analyzing both forward-scattered light and side fluorescence information, reticulocyte counts and reticulocyte maturity information were obtained. A PLT-O count was also performed in this channel. The ability to perform platelet counts by 2 different technologies provides more accurate platelet information. The sheath flow

86

J.Walters and P. Garrity

TABLE 1. Within-Run Precision (n = 10)* Sample 1 Mean Red blood cells, 106/µL 4.19 Hemoglobin, g/dL 12.1 Hematocrit, % 38.5 Impedance platelet count, 103/µL 351 White blood cells, 103/µL 12.39 Neutrophils, 103/µL 7.84 Lymphocytes, 103/µL 2.8 Monocytes, 103/µL 0.81

SD 0.03 0.06 0.30 3.00 0.16 0.15 0.07 0.05

Sample 2 CV, %* Mean 0.7 0.5 0.8 0.9 1.3 1.9 2.5 6.2

4.66 14 40.7 378 10.37 5.12 4.03 0.53

SD 0.03 0.05 0.20 6.00 0.10 0.08 0.10 0.04

Sample 3 CV, %

Mean

0.6 3.81 0.4 12.5 0.5 36.8 1.6 144 1.0 5.75 1.6 4.11 2.5 0.88 7.5 0.52

Sample 4

SD

CV, %

Mean

SD

0.02 0.03 0.20 2.00 0.11 0.08 0.07 0.09

0.5 0.2 0.5 1.4 1.9 1.9 8.0 17.3

4.13 12.6 38.3 217 5.18 2.94 1.13 0.45

0.03 0.00 0.20 5.00 0.10 0.06 0.06 0.04

Sample 5 CV, %

Mean

SD

0.7 4.58 0.01 0.0 13.3