Diagnostic error in a national incident reporting system in the UK

Diagnostic errors and delays carry potentially grave consequences for patients and feature prominently in studies of adverse events in health care. Diagnostic errors present a particular challenge for error/incident reporting systems because they involve clinical reasoning and are difficult to define precisely. The aim of the present study was to investigate what insights can be gained about diagnostic error from an incident reporting system.

Diagnostic errors reported to the UK's National Reporting and Learning System (NRLS) between November 2003 and October 2005 were investigated. We analysed reported level of harm to the patient and incident location and we compared diagnostic with non-diagnostic incidents. We also assessed the quality of reporting in a subset of reports associated with a patient's death.

Of 316,589 incidents reported in the period under investigation, 1674 were diagnostic (0.5%). Diagnostic incidents were more likely than other incidents to be associated with moderate or severe harm, or a patient's death and were more likely to occur in a hospital emergency department than other incidents. Diagnostic incidents in emergency departments were more likely to be associated with greater harm than similar incidents in wards. Observed reporting quality (detail; clarity) was very variable.

These findings replicate findings from studies in emergency departments and suggest that reporting systems have a role to play in understanding diagnostic errors alongside other sources of error analysis. Accurate and complete reporting of adequate volume enhances the potential contribution of an incident reporting system to understanding diagnostic error.