Development and Validation of a Penicillin Allergy Clinical Decision Rule
Trubiano et al. March 2020
JAMA Intern Med. 2020;180(5):745-752. doi:10.1001/ jamainternmed.2020.0403
Background
• Many patients self-report a penicillin allergy restricting antibiotic choice, and affecting antibiotic stewardship and local resistance patterns.
• Only 10% of self-reported penicillin allergies are confirmed.
• This prospective Australian study (n=622) sought to develop a point of
care clinical decision tool to identify the risk factors for a true penicillin
allergy
• Patients reporting a penicillin allergy underwent skin-prick testing,
intradermal testing, patch testing and/or an oral challenge (directly or
after skin testing).
• The prevalence of a positive penicillin allergy was 9.3%.
• The 4 factors associated with a positive result in the penicillin allergy test
are identified by the mnemonic PEN-FAST
• For patients reporting a PENicillin allergy:
• Five years or less since reaction (2 points)
• Anaphylaxis or angioedema OR
• Severe cutaneous adverse reaction (2 points)
• Treatment required for reaction (1 point)
0 points = Very low risk of positive penicillin allergy test <1% 1-2 points = Low risk of positive penicillin allergy test 5%
3 points = Moderate risk of positive penicillin allergy test 20% 4 points = High risk of positive penicillin allergy test 50%
• Using a cut-off of <3 gives a

• sensitivity of 70.7% • specificity of 78.5% • PPV of 25.3%
• NPV of 96.3%
• If a patient is low risk (ie <3), the study authors recommend an oral challenge in the ED prior to being sent home with a prescription.