Assessing delayed penicillin hypersensitivity using the PENFAST+ score.

Introduction: Approximately 10% of individuals report a suspected allergy to penicillin, but according to allergy work-ups, only 10%-15% of them are truly allergic. A clinical decision score, the PEN-FAST, was developed and validated to identify adults with low-risk penicillin allergy.

Objectives: The objective of this study was to improve the performance of the PEN-FAST score, particularly for those with delayed hypersensitivity (HS), by improving the negative predictive value.