Definitions in haemovigilance: guiding principles and current state of development of international reference definitions

Background Haemovigilance systems capture data on adverse reactions and infections in recipients of blood transfusions as well as on errors and incidents in the transfusion chain. The objective is to analyse them and make recommendations for improving transfusion safety. Many haemovigilance systems also collect data on complications in blood donors with a view to monitoring and improving blood donor safety. Standardized definitions are necessary for classifying and comparing data in all these domains and at all levels. Method Since 2004, at international meetings of blood transfusion professionals, members the International Haemovigilance Network ( IHN ) and the haemovigilance working party of the International Society for Blood Transfusion ( ISBT ) have collaborated in developing and validating definitions for non‐infectious transfusion complications, errors and incidents in the transfusion chain as well as adverse reactions in blood donors. From 2012, contacts with other groups including the World Health Organisation ( WHO ) have been put in place to ensure wide consultation as well as awareness and use of the definitions. Results Standardized definitions have been published for recipient adverse reactions, for complications of blood donation and for a limited number of types of incident in the transfusion chain. The ISBT haemovigilance working party and IHN are committed to ensuring that the definitions remain up‐to‐date and that revisions and improvements are conducted with wide consultation of professionals in relevant organizations worldwide. The haemovigilance working party and working party on transfusion‐transmitted infections are collaborating on the development of definitions and criteria for assessing suspected transfusion‐transmitted infections. Conclusion Internationally agreed definitions are available for registration and surveillance of complications of blood donation and most types of adverse reaction in patients receiving blood transfusions. For errors and incidents in the transfusion chain, further work is necessary to improve comparability of data between haemovigilance systems.