Diagnostic errors in an accident and emergency
H R Guly
Objectives—To describe the diagnostic
errors occurring in a busy district general
hospital accident and emergency (A&E)
department over four years.
Method—All diagnostic errors discovered
by or notified to one A&E consultant were
noted on a computerised database.
Results—953 diagnostic errors were noted
in 934 patients. Altogether 79.7% were
reasons for error were misreading radio-
graphs (77.8%) and failure to perform
radiography (13.4%). The majority of
errors were made by SHOs. Twenty two
diagnostic errors resulted in complaints
and legal actions and three patients who
had a diagnostic error made, later died.
Conclusions—Good clinical skills are es-
sential. Most abnormalities missed on
radiograph were not diYcult to diagnose.
Junior doctors in A&E should receive spe-
cific training and be tested on their ability
to interpret radiographs correctly before
being allowed to work unsupervised.
(Emerg Med J 2001;18:263–269)
Keywords: radiography; diagnostic errors
Diagnostic errors are important in all branches
of medicine as they are an indication of poor
patient care. Medically, the significance of a
diagnostic error in an accident and emergency
(A&E) department varies from minimal (for
example, a fracture of the terminal phalanx) to
potentially life threatening (for example, a
missed myocardial infarction). In other pa-
tients a delay in diagnosis may lead to less good
long term results (for example, tendon injury),
increased operative risks (for example, femoral
neck fracture) and pain and suVering until the
injury is diagnosed. However, all errors have
implications for patient care as even if the
medical consequences of an error are minimal,
patients are often distressed that an error has
been made and this may cause diYculty in
their relationship with the doctor or hospital.
There may also be costs to the hospital. In par-
ticular, diagnostic errors may bring com-
plaints, bad publicity and medicolegal costs.
The main reason for studying medical errors
is to try to prevent them. Reducing errors will
improve patient care,may reduce costs and will
improve the image of the hospital. However,
such study is also useful to facilitate learning,
to help to understand medical thinking and it is
reassuring to patients to know that errors are
investigated.1It is useful for risk management
as diagnostic errors are one of the commonest
causes of complaint and legal action against
A&E departments.2Research into “medical
accidents” (of which diagnostic errors are one
type) has been neglected and the problem
should be studied.1“Studies on the epidemiol-
ogy of malpractice are just as important as
studies of the epidemiology of disease . . .(as)
they allow insights into the causative factors
and ways of reducing the harm”.3
A&E departments are often staVed by very
junior doctors. Errors are not uncommon and
A&E is accepted as a “high risk” specialty.
Most of what is written about diagnostic errors
in A&E is in the form of case reports or
diagnostic diYculties with specific injuries (for
example, dislocated lunate,4carpometacarpal
tendon injuries6). Diagnostic
errors in patients with major injuries are
described in papers describing management
errors and deaths in such patients.7Papers
describing errors over a period of time usually
describe the misinterpretation of radiographs
(which is closely related but not necessarily the
same as diagnostic errors). The only previous
report of all errors in an A&E department was
a description of 135 diagnostic errors that
occurred over six months.8No study of missed
radiographs has been longer than a year.
The aim of this study is to describe,in detail,
the diagnostic errors occurring in an A&E
department over a four year period.
DEFINITION OF A DIAGNOSTIC ERROR
The definition of a diagnostic error was a diag-
nosis that could have been made in the A&E
department but that was not made until after
the patient left A&E.
x Patients in whom a diagnosis was missed by
an SHO but made by a more senior doctor
before the patient left the department.
x Diagnoses of, for example, “probable frac-
ture” or “possible fracture” were excluded
unless subsequent radiographs confirmed
that there was a fracture.
x False positive diagnoses.
x Injuries missed because initial radiographs
were normal were excluded. However, if
these radiographs were of poor quality or the
correct radiographic views had not been
requested, patients were included. It is
accepted that fractures of the scaphoid may
have normal radiographs at presentation and
that patients should be treated on clinical
suspicion and so fractures of the scaphoid
with normal initial radiographs that were
missed because no follow up was organised
Emerg Med J 2001;18:263–269263
Plymouth PL6 8DH,
Accepted for publication
19 July 2000
tendon injuries resulted in a complaint or
medicolegal claim. It is probable that the
reason for the diVerence is that most abnor-
malities missed on radiograph were discovered
either after a radiological report or at a clinic
review. The error was thus quickly identified
allowing doctors to treat where required and to
apologise. Injuries missed because of failure to
radiograph and other clinical errors (for exam-
ple, tendon injuries) will usually only be
discovered and rectified if the patient initiates a
further consultation. The vast majority of
errors do not result in complaints at present
but with increasing complaints and litigation,
the high number of errors is a cause for
How can the system be improved?
In the short-term, teaching should be
improved and guidelines on the use of A&E
radiology have been published.19However, this
cannot be expected to eliminate errors and it is
important to develop fail safe mechanisms to
detect errors when they occur. Radiology
departments should give priority to reporting
A&E films and the best solution is to have an
immediate reporting system.20
abnormal radiographs by radiographers can
assist in reducing diagnostic errors21but the
value of this may be limited by a high rate of
Better checks should reduce the number of
diagnostic errors caused by misreading radio-
graphs but it would be better to avoid such
errors completely. Better checks will not
reduce errors caused by failure to radiograph
or other clinical errors and as this type of error
is more likely to result in a complaint or legal
action, it may be considered more serious than
misreading radiographs. In the longer term, if
diagnostic errors are to be reduced, the system
should change to allow patients to be seen by
better trained doctors. Radiology trainees have
specific training in the interpretation of radio-
graphs and then work under supervision before
being allowed to interpret radiographs unsu-
pervised. Junior doctors in A&E should also,
ideally, receive specific training and be tested
on their ability to request and interpret
radiographs correctly before being allowed to
work unsupervised. This is not practical with
current methods of staYng. It has been stated
that is is unwise to roster an SHO for night
duty during their first week in A&E.23Even this
would be diYcult to organise for many A&E
departments and there is a need to increase the
level of middle grade and senior cover in A&E
departments to allow more patients to be seen
by more experienced doctors and for better
supervision of more junior doctors.
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Diagnostic errors in an accident and emergency department