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Inter-rater agreement in defining chemical incidents at the National Poisons Information Service, London
  1. I Abubakar1,
  2. G S Leonardi2,
  3. N Edwards3,
  4. N Herriott2
  1. 1Communicable Disease Surveillance Centre Eastern, Institute of Public Health, Cambridge and School of Medicine, University of East Anglia, Norwich, UK
  2. 2Chemical Incident Response Service, Guy’s and St Thomas’s NHS Hospital Trust, London, UK
  3. 3National Poison Information Service, Guy’s and St Thomas’s NHS Hospital Trust
  1. Correspondence to:
 Dr I Abubakar
 CDSC Eastern, IPH Cambridge CB2 2SR, UK;


Background: National surveillance for chemical incidents is being developed in the UK. It is important to improve the quality of information collected, standardise techniques, and train personnel.

Objective: To define the extent to which eight National Poison Information Service specialists in poison information agree on the classification of calls received as “chemical incidents” based on the national definition.

Design: Blinded, inter-rater reliability measured using the κ statistic for multiple raters.

Setting: National Poison Information Service and Chemical Incident Response Service, Guy’s and St Thomas’s NHS Trust, London.

Participants: Eight specialists in poison information who are trained and experienced in handling poisons information calls and have been involved in extracting information for surveillance.

Results: The overall level of agreement observed was at least 69% greater than expected by chance (κ statistic). Fire and incidents where chemicals were released within a property had a very good level of agreement with κ statistic of 83% and 80% respectively. The lowest level of agreement was observed when no one or only one person was exposed to a chemical (33%) and when the chemical was released into the air (48%).

Conclusion: High levels of agreement were observed. There is a need for more training and improvement in consistency of the data collected by all organisations.

  • Inter-rater agreement
  • chemical incidents
  • surveillance
  • toxicology

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  • Funding: none.

  • Conflicts of interest: none declared

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