| F - Five years or less since reaction | |
| A - Anaphylaxis or angioedema | |
| S - Severe cutaneous adverse reaction | |
| T - Treatment required for reaction |
Clinical decision rule for point-of-care risk assessment of patient-reported penicillin allergies.
Only patients who report a penicillin allergy are eligible for PEN-FAST.
A severe cutaneous adverse drug reaction includes Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS, or acute generalized exanthematous pustulosis. Acute interstitial nephritis, drug induced liver injury, serum sickness and isolated drug fever are not counted.