ABACUS (Alerts Based on ADR Causality and Severity)


No. Question Yes No Unknown N.A.
1 Is there a reasonable time interval between administration of the suspected drug and the adverse reaction?  
2 Has the adverse reaction been associated with the suspected drug before?  
3 Could this adverse reaction be due to an existing clinical condition?  
4 Is there any over-dose of the suspected drug?  
5 If the drug was discontinued, did the adverse reaction improve within a reasonable period of time?
6 If the drug was NOT discontinued, did the reaction resolved on its own?
7 Did the reaction improve when specific antagonist/antidote towards the suspected drug was administered?
8 Did the adverse reaction recur when the suspected drug was discontinued and re-administered?



Severity category Question  
S1 Offending drug may or may not be withheld, no treatment required
S2 Offending drug to be withheld, out-patient treatment is required
S3 Offending drug to be withheld, in-patient treatment is required
S4 Intensive care is required but patient does not suffer any disability
S5 Patient suffer irreversible harm (including physical disability)
S6 Patient died as a result of the reaction (either directly or indirectly)



Force calculations

Batch mode


ABACUS was developed in collaboration with Professor Shu-Chuen Li from University of Newcastle, Australia and Dr Yvonne Koh from National University of Singapore.

Please cite using: Koh Y, Yap CW, Li SC (2010). Development of a combined system for identification and classification of adverse drug reactions: Alerts Based on ADRs' Causality and Severity (ABACUS). Journal of the American Medical Informatics Association 17 (6): 720-722


Last modified on 7 February, 2012 by Yap Chun Wei