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Optimization of laboratory workflow in clinical hematology

laboratory with reduced manual slide review: comparison

between Sysmex XE-2100 and ABX Pentra DX120M. HUR*, J.-H. CHO*, H. KIM*, M.-H. HONG*, H.-W. MOON*, Y.-M. YUN*, J. Q. KIM

INTRODUCTION

The complete blood count (CBC) with leukocyte dif-

ferential counts (LDC) is one of the most frequently

requested tests in clinical laboratories. Technical evo-

lutions in automated hematology analyzers have

improved the analytic performance greatly and have

broadened the range of information provided (Buttarello

*Department of Laboratory

Medicine, Konkuk University

School of Medicine, Seoul, KoreaKonkuk University, Seoul, Korea

Correspondence:

Mina Hur, Department of

Laboratory Medicine, Konkuk

University School of Medicine,

Konkuk University Hospital, 4-12,

Hwayang-dong, Kwangjin-gu,

Seoul 143-729, Korea.

Tel.: +82 2 2030 5581;

Fax: +82 2636 6764;

E-mail: [email protected]

This work was supported by

Konkuk University in 2010.

doi:10.1111/j.1751-553X.2011.01306.x

Received 24 September 2010;

accepted for publication 21

December 2010

Keywords

Slide, review, Sysmex XE-2100,

ABX Pentra DX120, hematology

SUMMARY

Introduction: The validation of automated hematology analyzer results

by manual slide review (MSR) is currently an inevitable work process

in clinical hematology laboratories. The laboratory workload wouldbe optimized if the requirement for MSR could be reduced without

compromising patient care. We investigated whether slide-making

rates would be different between two hematology analyzers, which

were paired with their own automated slide makers/stainers: Sysmex

XE-2100 with SP-1000i (Sysmex, Kobe, Japan) and ABX Pentra

DX120 with SPS evolution (ABX-Horiba, Montpellier, France).

Methods: A total of 943 samples were run in parallel on the Sysmex

XE-2100 and ABX Pentra DX120. Reflex slides were automatically

made in each analyzer according to its own criteria, which reflected

the criteria of MSR in our laboratory. The slide-making rates were

compared, and the results were further confirmed using the criteriaof MSR.

Results: The slide-making rates in Sysmex XE-2100, ABX Pentra

DX120, and manual review were 22.5% (212/943), 15.91% (150/

943), and 11.5% (108/943), respectively. In 774 (82.1%) samples,

the three methods showed concordant results, and all made slides in

82 samples. Using the manual method as a standard, the sensitivity

and specificity were 86.1% and 85.8% in Sysmex XE-2100 and

89.8% and 93.7% in ABX Pentra DX120.

Conclusion: Our data show that the slide-making rates are variable in

different hematology analyzers. It also implies that although MSRcannot be fully substituted by modern hematology analyzers, it can

be effectively reduced to optimize laboratory workload.

ORIGINAL ARTICLE INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY

434 2011 Blackwell Publishing Ltd, Int. Jnl. Lab. Hem. 2011, 33, 434440

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RESULTS

The comparison data of slide preparation by Sysmex

XE-2100, ABX Pentra DX120, and manual review

are presented in Table 2. The slide-making rates in

Sysmex XE-2100, ABX Pentra DX120, and MSR were

22.5% (212/943), 15.91% (150/943), and 11.5%

(108/943), respectively. All the three methods showed

concordant results in 774 (82.1%) samples: all posi-

tive in 82 samples and all negative in 692 samples.

Discrepant results were observed in 169 samples. No

case showed a positive result by manual review but

Figure 2. Workflow of slide review with Sysmex XE-2100 and SP-1000i.

Figure 1. The decision-making criteria for manual slide review.

2011 Blackwell Publishing Ltd, Int. Jnl. Lab. Hem. 2011, 33, 434440

436 M. HUR ET AL. REDUCED SLIDE REVIEW IN HEMATOLOGY LABORATORY

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negative results by both Sysmex XE-2100 and ABX

Pentra DX120. However, there were discrepant results

between the Sysmex XE-2100 and ABX Pentra DX120

in 26 samples with positive MSR results: 15 were Sys-

mex negative and Pentra positive and the other 11were Sysmex positive and Pentra negative. Using

MSR as a reference method, the sensitivity and speci-

ficity were 86.1% (95% confidence interval (CI),

78.192.0%) and 85.8% (95% CI, 83.288.0%) in

Sysmex XE-2100 and 89.8% (95% CI, 82.594.8%)

and 93.7% (95% CI, 91.895.2%) in ABX Pentra

DX120, respectively (Table 3). Significant differences

in the specificity and specificity of the analyzers were

observed, with a difference of 3.7% (95% CI, 0.69

6.71; P = 0.0165) for sensitivity and 8.0% (95% CI,

5.210.8; P < 0.0001) for specificity (chi-square test).

The causes of false-positive and false-negative

results were analyzed (Table 4). In the 119 samples

with false-positive results by Sysmex XE-2100, slide

flag was the most frequent cause followed by delta

check and department; slide flag and/or delta check

comprised three-quarters (75.7%) of the total false-

positive causes. In ABX Pentra DX120, the two causes

of false-positive results were slide flag (64.2%) and

monocytosis with large immature cells (35.8%).

Regarding false-negative results, the causes were

department (n = 11) and absence of result (n = 4) in

Sysmex XE-2100, and absence of flag (n = 11) in ABX

Pentra DX120. The quantitative values or flags in 11

samples with false-negative results by ABX PentraDX120 are presented in Table 5. The Sysmex XE-2100

also showed flags and/or quantitative abnormalities

that triggered MSR in these 11 samples. However,

these did not correspond to our criteria for the

manual confirmation, except for one sample with 3%

basophils (sample 8).

DISCUSSION

The manual examination of blood smears is time-con-

suming and expensive and may not be always neces-

sary. To increase the clinical sensitivity, most

laboratories tend to develop less strict criteria so as

not to miss potentially important abnormalities. This

would be more conspicuous especially when a hospi-

tal has a large pool of hemato-oncological patients.

According to the College of American Pathologists

Q-Probes Study with 263 participating institutions,

the rates of MSR varied considerably among partici-

pants (26.7% in the median, 9.9% in the 10th per-

centile, and 50.0% in the 90th percentile institutions)

and were elevated with increased numbers of hospital

beds (Novis et al., 2006). That study showed that therates of MSR were directly related to the efficiency in

generating CBC results. Most of the MSR were trig-

gered by hematology analyzer flags, and these thresh-

old limits also varied widely among participants.

Recently, the use of automated slide makers and

stainers has increased in large-sized clinical laborato-

ries. They are used in combination with their multipa-

rameter hematology analyzers, and their performances

are reported to be comparable to well-prepared man-

ual processes (Simson, Gascon-Lema & Brown, 2009).

Compared with manual procedures, the introduction

of automated slide makers and stainers has signifi-

cantly reduced the workload of slide preparation as

well as the turn-around-time of the final CBC report.

On the other hand, not all the automatically prepared

slides are reviewed manually. If slide-making rules of

the instrument do not perfectly match the slide-review

criteria of the laboratory, there may be a discrepancy

between the prepared slides and reviewed slides. Con-

sidering the general policy of laboratories not to miss

Table 1. The rules for slide making in Sysmex XE-2100

Quantitative abnormalities

Leukocytopenia/leukocytosis: WBC < 2.0 109/l or

WBC > 20 109/l

Neutropenia/neutrophilia: neutrophils < 30% or

neutrophils > 85.5%

Lymphocytopenia/lymphocytosis: 70%

Monocytosis: monocytes > 15.5%

Eosinophilia: eosinophils > 20%

Basophilia: basophils > 2%

Nucleated RBCs > 2/100 WBCs

Thrombocytopenia/thrombocytosis: PLT < 100 109/l or

PLT > 600 109/l

Flags

PLT clumps or abnormal distribution

Fragments

Blasts

Immature granulocytesLeft shift

Atypical lymphocytes

Abnormal lymphocytes/lymphoblasts

WBC, white blood cell count; RBC, red blood cell count;

PLT, platelet count.


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any possible pathologic samples, the presence of these

unnecessarily prepared slides might be regarded as

inevitable. However, construction of the rules to

reflect the laboratories own criteria may be variable in

each hematology analyzer, and consequently, the gap

between the prepared and reviewed slides may be dif-

ferent. To the best of our knowledge, no study has

focused on this practical issue in routine hematology

laboratory so far.

This study investigated whether the slide-making

rates would be different between two hematology

analyzers when paired with their own automated slide

Figure 3. Workflow of the rules for slide making in Pentra DX120. PDX, ABX Pentra DX120; SPS, SPS evolution;

PML, Pentra multilink data management system.

Table 2. Slide preparation by Sysmex XE-2100, ABX

Pentra DX120, and manual review

Sysmex

XE-2100

ABX Pentra

DX120

Manual

review

Number

(%)

Positive Positive Positive 82 (8.7)

Positive Negative Positive 11 (1.2)

Negative Positive Positive 15 (1.6)

Negative Negative Positive 0 (0)

Negative Negative Negative 692 (73.4)

Positive Negative Negative 90 (9.5)

Negative Positive Negative 24 (2.5)

Positive Positive Negative 29 (3.1)

Positive means the slide preparation, and negative vice

versa.

Table 3. Comparison of the results between Sysmex

XE-2100, ABX Pentra DX120, and manual review

Sysmex XE-2100 ABX Pentra DX120

Positive Negative Positive Negative

Manual review

Positive

(n = 108)

93 15 97 11

Negative

(n = 835)

119 716 53 782


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makers/stainers: Sysmex XE-2100 with SP-1000i and

ABX Pentra DX120 with SPS evolution. Our data

showed that the sensitivity and specificity of slide

preparation were different between these two systems

and that the performance of ABX Pentra DX120

with SPS evolution was superior to that of Sysmex

XE-2100 with SP-1000i (Table 3). In particular, the

number of false-positive samples was decreased in

ABX Pentra DX120, and the main causes of difference

were attributable to delta check and department,

which could not be included in the rules for Sysmex

XE-2100 (Table 4). Department was also the main

cause of false-negative results in Sysmex XE-2100,

and in the routine practice of our laboratory, this was

one of the main causes of extra workload.

Eleven samples showed false-negative results by

ABX Pentra DX120 with no flags. In contrast, they

mostly showed flags of blasts, atypical lymphocytes, or

immature granulocytes and/or quantitative abnormali-

ties by Sysmex XE-2100 (Table 5). According to our

decision-making criteria for slide review, MSR was

triggered by the results of Sysmex XE-2100, and the

Table 4. Causes of false-positive and false-negative results by Sysmex XE-2100 and ABX Pentra DX120

Sysmex XE-2100 ABX Pentra DX120

False-positive Total (n = 119, 100%) Total (n = 53, 100%)Slide flag (n = 46, 38.7%) Slide flag (n = 34, 64.2%)

Delta check (n = 34, 28.6%) Mono + Lic (n = 19, 35.8%)

Department (n = 21, 17.6%)

Slide flag and delta check (n = 10, 8.4%)

Department and delta check (n = 8, 6.7%)

False-negative Total (n = 15, 100%) Total (n = 11, 100%)

Department (n = 11, 73.3%) No flag (n = 11, 100%)

No result (n = 4, 26.7%)

Mono + Lic, monocytosis and large immature cells.

Table 5. Quantitative values or flags in samples with false-negative results by ABX Pentra DX120

Dep

Quantitative values (%) or flags

ABX Pentra DX120 Sysmex XE-2100 Manual differential count (%)

1 IM Lic: 1.0 Abn L/L-Blasts N: 67, Nb: 2, L: 25, M: 6

2 IM E: 16.9 Eosinophilia, Blasts N: 65, L: 8, M: 8, E: 19

3 IM No flags Abn L/L-Blasts N:73, L:16, M:6, E:3, B:2

4 IM Lic: 1.0 Aty L N: 73, Nb: 2, L: 17, M: 4, E: 1, B: 2, Aty L: 1

5 IM Lic: 2.2 Immature Granulocytes N: 78, Nb: 2, L: 12, M: 4, E: 2, B: 1, Mm: 1

6 IM M:13.6, Lic: 0.4, Aty L: 1.5 Abn L/L-Blasts N: 43, Nb: 1, L: 39, M: 13, E: 3, B: 1

7 IM nRBC, platelet aggregates,

monocytosis, (M: 11.4,

Lic: 0.6, Aty L: 1.4)

Basophilia N: 65, Nb: 1, L: 22, M: 7, E: 4, B: 1

8 IM Lic: 0.8, Aty L: 0.9 Blasts N: 46, Nb: 2, L: 43, M: 6, B: 3

9 PED Neutropenia (M: 10.2,

Lic: 0.8, Aty L: 2.2)

Neutropenia,

Abn L/L-Blasts

N: 15, Nb: 4, L: 64, M: 11, E: 3, B: 2, Aty L: 1

10 IM Lic: 2.0, Aty L: 1.7 Aty L N: 79, Nb: 4, L: 10, M: 5, B: 1, Aty L: 1

11 IM M: 12.8, Lic: 0.9, Aty L: 1.4 Aty L N: 61, L: 25, M: 9, E: 2, Aty L: 3

Dep, department; IM, internal medicine; PED, pediatrics; Lic, large immature cells; Aty L, atypical lymphocytes; Abn L,

abnormal lymphocytes; nRBC, nucleated RBCs; L-Blasts, lymphoblasts; N, neutrophils; Nb, band-form neutrophils; L,

lymphocytes; M, monocytes; E, eosinophils; B, basophils; Mm, metamyelocytes; My, myelocytes.


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