Participants indicated that our questions were easy to follow and most commented that they enjoyed the interview as a good way to reflect on practice.
Definitions of diagnostic error
The definitions of diagnostic error provided by respondents were consistent with previous definitions. Over half of the 45 cases analysed were associated with the clinician focusing on a single diagnosis from presentation to closure of the cognitive process. Respondents divided errors into two different categories (G12): first, the wrong diagnostic label consisting of a diagnosis that's wrong or proven to be wrong by yourself or someone else at a later date (G3) and second, delayed diagnosis described as missed the boat you should have done something but you didn't (G2).
GPs raised two issues that caused difficulties in defining an error, namely variation in how to deal with the severity of the impact of the error: I rarely give someone a firm diagnosis … it would be an error if there was something serious and I had told someone [ it] wasn't (G8), and also what constitutes unacceptable delay given that lots of what we see is at low prevalence and evolving, so at the very front end it's very vague so actually most of that by definition should be delayed (G1).
Process of clinical reasoning in relation to diagnostic error
Results are reported with reference to the 45 cases and not individual GPs. The cohort provided sufficient data for a case-by-case analysis of errors, but not for comparing across the 15 GPs, though there were no indications of differing themes between individuals. The themes identified divided into two main groups: initiation and setting the initial diagnostic frame, followed by stopping the search for further clinical information and achieving diagnostic closure. Additional themes which emerged are also discussed.
Initiation and setting the initial diagnostic frame
Salient features link the individual clinician's personal knowledge of similar cases to the new presentation. A number of themes emerged from our analysis to shape the frame for the new case in its specific context. In most cases, GPs formed instantaneous diagnoses. For example, the patient's appearance—thought actually looked OK for a first child (G19),
or, she didn't sound too unwell over the phone (G9
)—before other information was available, provided a powerful bias for framing the case. In over 2/3 (31/45) of cases, the focus was on a single diagnosis, in about half of these based on presentation with a pre-existing diagnostic label (16/31). Box 1
reconstructs such a case.
Box 1. Case 27: illustration of initiation of the process and setting the initial diagnostic frame
The patient's history of previous psychosocial problems or abnormal behaviour, were predominant at this stage of the presentation: previous consultation which had set her up as a particular kind of person (4). Other salient features led GPs to instant recognition of a diagnosis or a limited number of differentials. For instance, just focusing on the vomiting (39), made the GP think of a gastric problem and delayed the diagnosis of an obstructed hernia. Wrong localisation framed the cognitive process and biased further information gathering, directly impacting on diagnostic closure thresholds.
Participants made repeated references to needing to focus on the natural history of disease and expected response to treatment. For instance, in referring to a case of missed cancer: people that have haemorrhoids that respond beautifully to treatment and have no other symptoms we don't tend to think, oh have they got a colonic cancer (14). Or, the need for experience: lacked experience at that time [to] potential of this case…. and work on the possible diagnosis (9). Most of these references to experience were suggestive of knowledge gaps rather than cognitive error only. Further examples of biases arising from the initial framing appear in .
Biases arising from salient features of presentation which initiate the diagnostic process and frame the direction of subsequent information gathering
Conditions and thresholds for diagnostic closure
Participants did not use numerical criteria to describe the thresholds they used to decide when to stop searching for more clinical information. Nor did they express confidence in their decisions this way. When pressed, some responded in terms such as: the test would exclude X in 70% of cases, or I was more than 80% certain that I excluded Y, but the basis for these numerical values was very unclear. Since we felt that a number of participants found these questions judgmental, we therefore dropped them as the interview schedule progressed.
A number of GPs raised safety netting spontaneously, or in response to our questions, related to diagnostic closure. It soon became apparent that recollections were hazy and they were unsure as to whether they actually used safety netting, or just thought that they should have. Therefore, we do not include safety netting in our analysis, recognising its importance as a potential cause of error.
The decisions made at closure were affected by biases from the setting of the initial frame, effectively impeding the reflective System 2 review expected at this stage. Box 2
is a reconstruction of such a case to provide insights into how the relationship between biases formed at initiation may affect decisions at closure.
Box 2. Case 14: illustration of dominant System 1 impeding System 2 review at closure, leading to error
Other themes related to diagnostic errors after ignoring or misinterpreting the predictive value of critical information coming from the patient, as did ignoring ‘gut feelings’.21
Other respondents noted the need to be circumspect when responding to patient needs, including poor outcome with a patient who did not wish to follow advice: had a cruise booked and he chose to cancel the appointment and go on the cruise (15).
Some GPs raised issues about their own behaviours: one's own state of confidence or call it what you want competence confidence arrogance or risk taking or not risk caution all play in the actual what you decide to do (12); I'm right at one end of low referrers (43).
Contextual factors were often raised as contributing to faulty decisions: [knowing how busy it is before a week end] do I want to send a frail, elderly lady up to the hospital on a Friday afternoon when it would be mayhem [there] (34);
explaining a missed diagnosis: we were really busy and I think they came in as an emergency (39).
provides examples of biases affecting thresholds for ruling disease in or out.
Effect of framing biases on closure thresholds for ruling disease in or out