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Validation of a diagnostic reminder system in emergency medicine: a multi-centre study
  1. Padmanabhan Ramnarayan1,
  2. Natalie Cronje2,
  3. Ruth Brown3,
  4. Rupert Negus3,
  5. Bill Coode4,
  6. Philip Moss4,
  7. Taj Hassan5,
  8. Wayne Hamer5,
  9. Joseph Britto6
  1. 1Children’s Acute Transport Service, London, UK
  2. 2Isabel Healthcare, London, UK
  3. 3St Mary’s Hospital, London, UK
  4. 4Newham General Hospital, London, UK
  5. 5Leeds General Infirmary, Leeds, UK
  6. 6Isabel Healthcare, Reston, VA, USA
  1. Correspondence to:
 Padmanabhan Ramnarayan
 44 B Bedford Row, Children’s Acute Transport Service, London WC1R 4LL, UK; ram{at}


Background: Diagnostic error is a significant problem in emergency medicine, where initial clinical assessment and decision making is often based on incomplete clinical information. Traditional computerised diagnostic systems have been of limited use in the acute setting, mainly due to the need for lengthy system consultation. We evaluated a novel web-based reminder system, which provides rapid diagnostic advice to users based on free text search terms.

Methods: Clinical data collected from patients presenting to three emergency departments with acute medical problems were entered into the diagnostic system. The displayed results were assessed against the final discharge diagnoses for patients who were admitted to hospital (diagnostic accuracy) and against a set of “appropriate” diagnoses for each case provided by an expert panel (potential utility).

Results: Data were collected from 594 patients (53.4% of screened attendances). Mean age was 49.4 years (95% CI 47.7 to 51.1) and the majority had significant past illnesses. Most were assessed first by junior doctors (70%) and 266/594 (44.6%) were admitted to hospital. Overall, the diagnostic system displayed the final discharge diagnosis in 95% of inpatients and 90% of “must-not-miss” diagnoses suggested by the expert panel. The discharge diagnosis appeared within the first 10 suggestions in 78% of cases.

Conclusions: The Isabel diagnostic aid has been shown to be of potential use in reminding junior doctors of key diagnoses in the emergency department. The effects of its widespread use on decision making and diagnostic error can be clarified by evaluating its impact on routine clinical decision making.

  • DDSS, diagnostic decision support systems
  • ED, emergency department
  • RA, research assistant
  • diagnostic error
  • diagnostic decision support system
  • diagnostic accuracy
  • reminder system

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  • Funding: This study was supported by a research grant from the National Health Service (NHS) Research & Development Unit, London. The sponsor did not influence the study design; the collection, analysis, and interpretation of data; the writing of the manuscript; or the decision to submit the manuscript for publication.

  • Competing interests: The Isabel system is currently managed by Isabel Healthcare, and is available only to subscribed individual and institutional users. Dr Ramnarayan is a part-time research advisor for Isabel Healthcare, Ms Cronje was employed as a research assistant by Isabel Healthcare for this study, and Dr Britto is Clinical Director of Isabel Healthcare. All other authors declare that they have no competing interests.

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