Background: A standardized and generally applicable scheme for grading the severity of poisoning allows a qualitative evaluation of morbidity and facilitates comparability of data. Working from a simple grading scale proposed by the European Association of Poisons Centres and Clinical Toxicologists, a Poisoning Severity Score has been developed jointly with the International Programme on Chemical Safety and the European Commission.
Methods: The Poisoning Severity Score has been elaborated, tested, and gradually revised during a project running 1991-1994. Fourteen poisons centers from various countries have participated. Each center independently graded 371 cases of acute poisoning by ten different toxic agents. The data were then analyzed and compared.
Results: The concordance in grading the severity increased during the study period, and in the last phase there was an acceptable concordance among centers in 80% or more of the cases. Given the condition and quality of the original case records, this result was considered satisfactory and agreement was reached on the scoring scheme presented here. The Poisoning Severity Score grades severity as (0) none, (1) minor, (2) moderate, (3) severe, and (4) fatal poisoning. It is intended to be an overall evaluation of the case, taking into account the most severe clinical features. Use of the Poisoning Severity Score normally requires a follow-up of all cases, but may be used on admission or other times during the course of poisoning if this is clearly stated when data are presented.
Conclusions: A Poisoning Severity Score has been developed and found applicable for grading the severity of poisoning. It is foreseen that the Poisoning Severity Score will meet the expectations and be used in practice, but its future use and evaluation may result in some further revision and refinement.