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Mounira Khoury, Leslie Burnett and Mark A Mackay
MJA 1996; 165: 128-130
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Abstract - Introduction - Methods - Measurement criteria - Participants - Survey - Statistical analysis - Results - Participation - Transcription errors - Analytical performance - Combined error rates - Discussion - Acknowledgements - References - Authors' details
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©MJA1996
In its most common diagnostic setting, the process of requesting
pathology tests seems simple: the doctor writes a request, the
pathology laboratory interprets the request, transcribes
information from the request form to its computer system, performs
the analysis, and the pathologist produces a printed report for
return to the doctor. This process assumes that the patient has been
correctly identified, an appropriate specimen has been obtained,
analysis has been correctly performed, and the results of analysis
have been communicated to the original requesting practitioner.
We recently examined the accuracy of one part of the process of
obtaining pathology test results in a hospital environment and found
that the address of the referring doctor had been incorrectly
recorded on 3% of all printed reports issued, delaying or preventing
delivery of the final pathology report. 3 If this rate of error were typical for
the many other steps of the requesting process for pathology tests,
then the total error rate in obtaining results would be extremely
high.
To address this question, we surveyed clinical pathology
laboratories from both public and private sectors of five Australian
States to determine whether error rates in pathology are as
widespread and as clinically significant as our earlier study
suggested.
Methods
One hundred hand-written pathology request forms dated between 1
November 1993 and 1 April 1994 were randomly selected by the
participating laboratories. We excluded request forms which also
contained requests for blood transfusion or tissue pathology
because some laboratories adopt more stringent identification
criteria for these types of specimens. Laboratories scored the
number of transcription errors (defined as any instances where the
data on individual request forms were not identical to the data
entered into the laboratory's computer system 5 ).
Chemical pathology quality assurance (QA) data were from one cycle of
analysis within the QA program (there are two or three cycles
annually, depending on the program) during 1993 and 1994.
Laboratories scored the total number of QA samples analysed, and the
proportion of results of these analyses that lay outside the
allowable limits of error of the QA program.
All data, as well as a summary of the relative performance of all other
participants (each assigned a number so that they were not
identifiable), were returned to each laboratory for validation
before final analysis.
The Figure shows that, while two laboratories were able to achieve
overall transcription-error rates of less than 3%, four had error
rates more than two standard deviations above the mean error rate
(13%) of participating laboratories ( P < 0.05). The
laboratory with the poorest performance reported a
transcription-error rate of 39%.
The two laboratories which showed the poorest performance reported
transcription errors or unacceptable ana lytical performance in
more than a third of all requests. They were both hospital
laboratories from the same State. Their high total error rates were
particularly influenced by transcription errors.
Discussion
This pilot survey of laboratory performance is the first of its kind to
have been done in Australia. Previous studies have reported
particular types of laboratory errors (e.g., patient ward location
or address) in 0.08% 6
to 3% 3,6,7 of requests.
We have confirmed that median error rates for individual types of
errors in routine pathology requests are of the order of 3% 3 (see Box 2), and overall error rates
can be as high as 46%.
While some of the laboratories operated with few or no errors, eight of
the fourteen reported significantly inferior performance
(Figure). Further, our findings indicate that some laboratories may
be making transcription errors in up to 39% of all request forms, and
can have error rates of 9% in patient identification data and 17% in
data such as sex and date-of-birth. Such error rates should be a cause
of clinical concern.
Risk management in pathology laboratories recognises the
relationship between proper identification of specimens and the
prevention of adverse patient-care-related incidents. 2 Our study was not designed to trace
particular errors to final clinical outcomes, or to distinguish
between errors on the basis of severity. However, it would be
surprising if transcription-error rates of the magnitude we
encountered did not contribute to adverse clinical outcomes.
Are the errors caused by the requesting doctor, or by the laboratory?
Several laboratories used direct electronic capture of patient data
from a database, which should minimise errors in patient
identification data arising from illegible handwriting.
These laboratories did not have lower rates of transcription error
for patient identification data than those relying solely on
handwritten pathology requests. Indeed, the two laboratories with
the highest overall rates of transcription error both obtained their
patient identification data from a central database. This leads us to
conclude that poor handwriting by the requesting doctor was not the
major factor in high rates of transcription errors.
Errors in pathological tests come at a considerable cost to the
community. Expenditure on pathology investigations in Australia
amounts to some $1.4 billion -- approximately 4% of total health
services expenditure (Australian Association of Pathology
Practices, personal communication). Incorrect tests being
performed in up to 15% of cases wastes medical resources. Requesting
doctors being incorrectly identified on up to 17% of requests will
result in laboratories incurring unnecessary delivery costs and
doctors incurring additional costs, as they will need to obtain
duplicate copies of reports not delivered, and will request repeat
testing for results unable to be located.
We believe that most of these errors could have been prevented by the
laboratories. The three best-performing laboratories in our study
used different equipment and computer systems, and operated in both
public and private sector environments. We therefore suggest that
superior overall performance can be achieved by controlling error
rates at each step in the process, and that this can be done in diverse
ways.
All recognised medical testing laboratories within Australia are
required to be accredited, and to participate in QA programs for
analytical quality. However, there are no minimum standards of
performance which laboratories are required to maintain within
these QA programs. There are also no Australian QA programs which
monitor non-analytical aspects of pathology laboratories, such as
transcription errors. We recommend that QA programs should be
introduced for a range of clinically important areas of laboratory
performance, such as request transcription accuracy, transport and
analysis times for key analytes (e.g., potassium), rapid reporting
of critical patient data, and client satisfaction, in addition to
existing programs for analytical quality. We also recommend that
summaries of actual and achievable performance in these QA programs
be published.
Without laboratory participation and satisfactory performance in
such programs, doctors cannot be confident that test results are
correct. Indeed, they cannot even be confident that the result was
obtained for the correct patient. Lower error rates in pathology
tests should lead to improved patient outcomes and less wastage of
health resources.
Acknowledgements
We thank the staff of the participating laboratories for their
assistance with this study. We are grateful to Elizabeth Benson, Jon
Currie, Jeremy Chapman, Doug Chesher and Ruth Pojer for their
critical comments on the manuscript.
References
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© 1996 Medical Journal of Australia.
Abstract
Objective: To measure transcription and analytical
errors made by Australian chemical pathology laboratories.
Design: Retrospective data collection covering the
period 1 November 1993 to 1 April 1994.
Setting and participants: Fourteen pathology
laboratories in five Australian States (seven in the public sector,
and seven in the private sector).
Main outcome measures: Error rates in transcribing
information from request forms to computer record systems, and
laboratory performance on chemical analysis.
Results: Pathology laboratories had a
transcription-error rate of up to 39% and an error rate of up to 26% for
analytical results. The worst-performing laboratory had errors (of
patient identification or results of analysis) in 46% of requests.
The three best-performing laboratories achieved 85% error-free
reporting, with one achieving 95%.
Conclusions: Error rates in Australian pathology
laboratories vary widely, but may be as high as 46% for all specimens in
some laboratories. The types of errors reported were under the
control of the laboratory, and would affect the accuracy of reported
pathology test results, with potential adverse outcomes for patient
care and inefficient use of health-care resources. There is a need to
establish broader quality assurance programs and performance
requirements to reduce these types of error.
MJA 1996; 165: 128-130
Introduction
T he Quality in Australian Health Care Study 1 described an unacceptable rate of
preventable adverse events involving patients which occur in
Australian hospitals. Errors introduced into the process of
requesting pathology tests can adversely affect patient management
and will detract from quality of care and services. 2 At best, a sample may need to be
collected again to repeat the analysis, inconveniencing the
patient, delaying treatment and increasing the cost. At worst, a
doctor may act on incorrect results and the patient may be treated
inappropriately.
Measurement criteria
We identified potential indicators using national Quality Award
criteria for benchmarking indicators, 4 focusing on factors affecting
medical outcomes which arose from the pathology laboratory. In this
paper, we report on transcription errors and analytical performance
in chemical pathology quality assurance programs. Details of these
criteria and how they were measured are shown in Box 1. We did not
examine how laboratories functioned to deliver these outcomes.
Participants
We approached 18 large National Association of Testing
Authorities-registered laboratories, well recognised in the
industry, representing both public and private sectors, in
five Australian States (Queensland, New South Wales, Victoria,
Tasmania and South Australia).
Survey
Survey forms, which included detailed instructions and operational
defini tions of the information required, were completed by the
laboratories between 1 May and 31 July 1994.
Statistical analysis
Data analysis was based on the binomial distribution. 5 Calculation of combined error rates
was based on the product of constituent error-free components, with
the standard deviation calculated from the sum of variances of
individual component errors.
Results
Participation
Fourteen laboratories (seven public and seven private, numbered
1-14 to preserve anonymity) completed the entire benchmarking
study; all five States were represented.
Transcription errors
Box 2 shows our findings for particular types of transcription
errors. Most laboratories lay within a tight distribution clustered
around median error rates of 1% to 3%. For each transcription error
listed, a single outlier -- a different laboratory in each case --
performed particularly badly.
Analytical performance
Laboratories recorded errors outside the allowable limits of error
in up to 26% of analytical results. As shown in the Figure, four
laboratories reported unacceptable performance more than two
standard deviations above the mean rate (11.4%) of participating
laboratories ( P < 0.05).
Combined error rates
By matching the transcription-error rate with analytical
performance, we were able to measure the proportion of all pathology
requests that would have been free of either type of error (Figure).
Three laboratories showed superior performance compared with
peers, achieving 85% error-free reporting, with one achieving 95%
error-free reporting (a total error rate of less than 5%). These three
laboratories represented both the public and private sectors, were
all from different States, and each used a different computer system
and clinical chemistry analyser.
(Received 20 Nov 1995, accepted 22 May 1996)
Authors' details
Faculty of Clinical Chemistry, School of Life Sciences, University
of Technology (Gore Hill Campus), Sydney, NSW.
Mounira Khoury, MSc(Clin Biochem), Graduate Student.
Institute of Clinical Pathology and Medical Research, Westmead
Hospital, Sydney, NSW.
Leslie Burnett, PhD, FRCPA, Director of Clinical Chemistry.
Mark A Mackay, MSc, Hospital Scientist and Quality
Facilitator.
Reprints: Associate Professor Leslie Burnett, Assistant
Director, Institute of Clinical Pathology and Medical Research,
Westmead Hospital, Westmead, NSW 2145.