Question and Methods: Prospective derivation and subsequent retrospective validation of a clinical decision rule for the detection of patients at low risk for true penicillin allergy.
Findings: The PEN-FAST rule has an NPV of 96.3% for predicting those at low risk for true penicillin allergy.
Limitation: The external validation was done retrospectively and the study did not provide any safety data on the consequences of false-negative results.
Interpretation: The PEN-FAST rule has limited use in the ED as most patients may be too unwell to undergo the therapeutic penicillin challenge.
By: Dr. Tina Chiang
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