ISLH
Laboratory Hematology 7:85-88
© 2001 Carden Jennings Publishing Co., Ltd.
Official Publication
The Use and Interpretation of Quantitative
Terminology in Reporting of Red Blood
Cell Morphology
LAWRENCE HOOKEY, DAVID DEXTER, DAVID H. LEE
Departments of Medicine and Pathology, Queen’s University, Kingston, Ontario, Canada
ABSTRACT
INTRODUCTION
Despite advances in diagnostic technology in the hematology laboratory, the evaluation of peripheral blood films for
abnormal red blood cell (RBC) morphology remains a manual task. The terminology used by laboratory technologists to
describe the frequency of morphologically abnormal RBCs in
peripheral blood films has rarely been studied. We conducted
a study to determine the variability in the use of these quantitative descriptors and to determine how physicians interpret
these terms. Thirty-one hematology laboratory technologists
from 6 hospitals were asked to quantitate abnormal RBCs in
a series of peripheral blood films using their usual terminology.
Interpretation of these quantitative terms by the attending
physicians and residents from an Internal Medicine teaching
program was also assessed. We found a wide variation in the
use of quantitative descriptors between technologists and
between centers. Physicians’ interpretations of these terms
varied, with some terms having a narrow, consistent interpretation and others having a broader range of interpretations.
We suggest that the precision of communication between the
hematology laboratory staff and clinicians can be improved
by tailoring the use of quantitative terminology to avoid
terms that have a broad range of interpretations by physicians. Lab. Hematol. 2001;7:85-88.
Despite advances in diagnostic laboratory technology, the
assessment of peripheral blood films for red blood cell
(RBC) morphologic abnormalities remains a manual task
that is inherently subjective. The frequency of morphologically abnormal RBCs (such as target cells or schistocytes) in
a blood film can have significant implications on diagnosis
and clinical management; therefore, quantitative descriptors
(such as rare or occasional) are frequently included in morphology reports. Accurate communication of the frequency
of abnormal RBCs is entirely dependent on the wording
used in morphology reports; however, this aspect of laboratory practice has not been studied or evaluated in quality
assurance programs. We conducted a study to determine the
variability in the quantitative terminology used by laboratory technologists to describe the frequency of abnormal
RBCs in a set of standard peripheral blood films. We also
surveyed physicians to ascertain how they interpreted these
quantitative descriptors.
KEY WORDS:
METHODS
Assessment of Terminology Used by Laboratory
Technologists
Clinical laboratory technologists from one tertiary care
teaching hospital in Kingston, Ontario and 5 non-teaching
hospitals in southeastern Ontario were invited to participate
if reviewing peripheral blood films was a routine part of their
laboratory responsibilities. A standard set of 7 peripheral
blood–film slides depicting target cells (2 slides), schistocytes
(2 slides), teardrop cells (1 slide), acanthocytes (1 slide), and
RBCs containing Howell-Jolly bodies (1 slide) were prepared
with Wright’s stain [1], and viewed by all participants using
Red blood cell · Morphology ·
Reporting · Interpretation
Correspondence and reprint requests: David H. Lee, Etherington Hall,
Queen’s University, 94 Stuart Street, Kingston, Ontario, Canada, K7L 3N6;
(613) 533-6329; fax: (613) 533-6855 (e-mail:leedh@meds.queensu.ca).
Received January 3, 2001; received in revised form April 3, 2001;
accepted April 4, 2001
85
86
L. Hookey et al
Quantitative descriptors used by technologists and their interpretation by physicians. The upper 7 panels depict the frequencies of
terms used by technologists to describe the quantity of abnormal red blood cells in a set of 7 peripheral blood films. The lower panel
depicts the physicians’ interpretation of the terms: the mean (), standard deviation (error bars), and minimum and maximum values () are shown for each term. Results of statistical comparison between physician interpretations of terms are shown in Table 2.
their usual microscopes in their own laboratories. For each
slide, the type of abnormal RBC to be quantitated was given,
and each technologist selected the quantitative descriptor
that they would normally use to report the frequency of the
abnormal RBC from a list of terms. The list of terms was
generated after consultation with technologists prior to the
study. Technologists were observed during the study to
ensure that no collaboration occurred.
list. This was done using 0 to 10 ordinal scale for each term,
anchored at each end by the terms none and all, respectively.
Interpretation of Terminology by Physicians
Residents and attending physicians in the Internal Medicine training program at Queen’s University in Kingston,
Ontario were surveyed to determine how frequent they perceived a morphologic abnormality to be for each term on the
Thirty-one technologists from 6 hospitals and 32 physicians from 1 hospital participated. The responses of laboratory
technicians are shown in the Figure. Responses were heterogeneous for all slides. For 6 of the 7 slides, fewer than
half of participants used the same term to describe the
Statistical Analysis
The Wilcoxon signed rank test was performed to compare
paired physician responses.
RESULTS
Quantitative Terminology in Reporting of Red Blood Cell Morphology
87
TABLE 1. Frequency of Terminology Used by Each Center
Centers
No. of technologists
Terminology used
Rare
Slight
Occasional
Few
Mild
Present
Moderate
Many
Marked
Other
All
1*
2
3
4
5
6
31
11
4
4
4
5
3
10
16
28
44
1
36
50
12
4
16
4
9
20
17
1
4
16
4
1
1
0
5
5
6
0
0
10
2
0
0
5
0
0
6
0
0
14
0
1
2
1
0
3
10
0
1
7
4
1
1
0
0
0
0
0
30
0
0
0
5
0
2
0
5
0
1
3
2
1
7
*Tertiary care center.
frequency of the abnormality. Certain terms were used more
frequently by certain centers (Table 1). The term rare was
used mainly in centers 1 and 3. Slight was used primarily in
centers 1 and 2. Occasional was used primarily in center 1
and present was used almost exclusively in center 5.
The physicians’ interpretations of the terms used by the
technologists are arranged in ascending order (Figure, lower
panel). When pairs of terms were compared, the differences
in interpretation between most terms were found to be statistically significant (Table 2), but the magnitudes of the differences between some terms is small. There was heterogeneity
in the scatter of responses to the terms (Figure, lower panel).
For example, the term rare had little variation in perceived
meaning: all responses were clustered at the low end of the
scale. In contrast, the term present had a broader meaning to
physicians, with responses distributed over a wider range.
DISCUSSION
In this study, we observed heterogeneity in the quantitative terms used by laboratory technologists to report the fre-
quency of RBC morphologic abnormalities. This variation
was present between centers and between technologists. Furthermore, many of the different quantitative terms used to
describe the same blood film are interpreted differently by
physicians. To our knowledge, these aspects of hematology
morphology reporting have not been studied previously.
The current study focused on the responses of technologists and physicians, rather than on the variables that contributed to these responses. Likely, the choice of terminology
by technologists is dependent on several variables including
(1) the perceived frequency of the abnormality by the technologist, (2) the perceived meaning of the various terms by
the technologist, and (3) laboratory policy and local practices. Similarly, the interpretation of these terms by physicians is likely influenced by (1) the physician’s concept of the
terminology, (2) their familiarity with abnormal RBC morphology and its reporting, and (3) previous exposure to the
terminology. The latter 2 influences are probably dependent
on the specialty and experience of the physician and may also
depend on existing regional reporting practices to which the
physician is accustomed. Although the physicians surveyed
TABLE 2. Wilcoxon Signed Rank Test P Values for Comparison of Physicians’ Interpretations of Quantitative Terms
Slight
Present
Moderate
Few
Mild
Marked
Occasional
Many
Rare
Slight
Present
Moderate
Few
Mild
Marked
Occasional
Many
Rare
—
<.001
<.001
<.001
.001
<.001
.001
<.001
<.001
<.001
—
.039
.003
.012
<.001
.002
<.001
<.001
<.001
.039
—
<.001
<.001
<.001
<.001
<.001
<.001
<.001
.003
<.001
—
.174
<.001
.197
<.001
<.001
.001
.012
<.001
.174
—
<.001
.013
<.001
<.001
<.001
<.001
<.001
<.001
<.001
—
<.001
<.001
<.001
.001
.002
<.001
.197
.013
<.001
—
<.001
<.001
<.001
<.001
<.001
<.001
<.001
<.001
<.001
—
<.001
<.001
<.001
<.001
<.001
<.001
<.001
<.001
<.001
—
88
L. Hookey et al
represent a single specialty rather than a general cross-section
of physicians, they do make up a specialty (Internal Medicine) that is an important consumer of laboratory information. It is not known whether the observed technician and
physician responses are generalizable, nor is it known
whether the differences in terminology use or interpretation
are of sufficient magnitude to affect clinical management.
Understanding how clinicians interpret quantitative terminology may lead to improved patient care. For example,
avoiding the use of terms that are vague (eg, the term present)
might improve the usefulness of the morphology report.
Recognition of the limitations of specific words and the
inconsistent use of terminology may also be relevant for laboratory quality improvement. Hematology laboratory external
quality assessment programs evaluate blood film interpretation [2,3] but quantitation of abnormal cells is infrequently
evaluated, partly because of the inconsistent distribution of
abnormal leukocytes in blood films. To our knowledge, the
distribution of the abnormal non-nucleated RBCs examined
in our study would not be expected to vary significantly from
region to region within the same slide.
Based on the results of our study, we do not recommend
the use of the term present as a quantitative descriptor for RBC
morphology reporting because of the wide variation in meaning to clinicians. To minimize the risk of being misunderstood,
laboratory technologists should be encouraged to use terms
that have relatively uniform interpretations and to recognize
that terms used by individual technologists may have a different meaning to clinicians. Although we did not ascertain how
technologists judge the same panel of terms, similar patterns of
variability of interpretation likely exist within this group.
How can each hematology laboratory optimize its choice
of quantitative descriptors? We believe that the local clinicians who regularly use the laboratory should be surveyed as
was done in our study. In this fashion local tendencies and
differences can be taken into account when selecting a menu
of quantitative descriptors for use in reports. Such a survey
need not be cumbersome: our physician survey took approximately 1 minute to complete, and our group of 32 physicians
in a tertiary care center were surveyed in 1 day. We propose
that these measures and further study of quantitative
descriptors in peripheral blood film reporting will improve
the precision of communication between the hematology
laboratory and clinicians.
REFERENCES
1. Luna LG. Histopathologic Methods and Color Atlas of Special Stains
and Tissue Artifacts. Gaitheresburg, Md: American Histolabs;
1992.
2. Lewis SM. The WHO International External Quality Assessment
Scheme for haematology. Bull World Health Organ. 1988;66:283-290.
3. Lewis SM. Blood film evaluations as a quality control activity. Clin
Lab Haematol. 1990;12(suppl 1):119-127.