BackgroundPenicillin allergy is reported in 10% patients in the US Patients with penicillin allergies are treated with broader spectrum antibiotics, often leading to more antibiotic-resistant infections, including C. difficile, increased risk of surgical site infections, and increased healthcare costs.MethodsAfter informed consent, Medical-Surgical patients with documented allergies to penicillin (P) or cephalosporins (C) were given challenge doses through a standardized 2-step protocol from June 2015 to November 2017 at our community hospital. Patients with documented IgE-mediated hypersensitivity (HSR), rash or unknown reactions were eligible. Those with anaphylaxis or Type II-IV HSR were excluded. Treating clinicians selected the antibiotic for testing guided by the protocol: 323/336 patients (96%) were challenged with C. Based on results, allergies were updated in patients’ charts, noting that tolerance of cephalosporins does not preclude penicillin allergy. Charts were reviewed to determine adverse events and antibiotic narrowing, the latter adjudicated by ID specialists not directly involved in the patient’s care. A cost analysis used the acquisition cost of administered antibiotics before and after testing.Results336 patients (53 Medical, 283 Surgical) underwent the allergy test dose protocol: 267 with reported P allergy, 47 C allergy, 22 P+C allergy. None had a major adverse reaction. 7 patients (2%) experienced minor reactions: rash (4), throat irritation (1), urticaria (1), wheezing (1). Before testing, 321/336 were prescribed inappropriate or broad antibiotics. After challenge dose testing, the antibiotic spectrum was narrowed in 308/321 (96%). The total Pharmacy cost savings was $38,281.00 with the optimized antibiotic regimen, translating to $630 saved per patient. In Surgical patients there was a 50% cost savings.ConclusionDespite the frequency with which β-lactam allergies are reported, few patients had an allergy that interfered with optimal treatment when tested. This standardized protocol can be safely performed in a community hospital setting and lead to improved antibiotic choice and pharmacy cost savings.ReferenceIammateo M et al, J Allergy Clin Immunol Pract, November 2014; 2, 768–74.Disclosures All authors: No reported disclosures.