The Ontario Transfusion Transmitted Injuries Surveillance System (TTISS-ON) Education Committee’s transfusion reaction app, based on the paper transfusion reaction chart, intended to provide guidance to nurses, physicians and Blood Transfusion Laboratory personnel on how to identify, investigate and treat transfusion reactions by symptom presentation. TTISS-ON is part of the national hemovigilance system TTISS for reporting transfusion reactions, implemented in 2001 by the Infectious Disease Prevention & Control Branch of the Public Health Agency of Canada.