2024 FSA Podium and Poster Abstracts

P016: PHARMACIST-LED OUTPATIENT PENICILLIN ALLERGY TESTING CLINIC
Eric C Linn, PharmD; Adam Fier, DO; Michael Sanchez, PharmD; Brekk DelHomme, PharmD; Meera Baldeosingh, PharmD; Theodore Heierman, PharmD; John Perry, MD; Norman Tomaka, BS, Pharmacy; Health First Holmes Regional Medical Center

Penicillin allergies affect approximately 10% of the population, leading to increased healthcare costs, treatment failures, and multidrug resistant organisms. The objective of this study was to assess the feasibility and implementation of pharmacist-led outpatient penicillin allergy testing clinic. Penicillin allergy skin testing (PST) is recommended to facilitate optimizing antibiotics by the American Academy of Allergy, Asthma, and Immunology (AAAAI), Infectious Disease Society of America (IDSA), and the American College of Obstetricians and Gynecologists (ACOG). With a projected shortage of physicians, including allergists and immunologists by 2034, pharmacists are in a prime position to collaborate with anesthesiologists to provide penicillin allergy testing and optimize antibiotics prior to planned surgical procedures.

This single-site, retrospective cohort evaluated the implementation of outpatient PST conducted by pharmacists from July 2022 through December 2023. The study site consisted of an outpatient clinic within a non-academic community hospital. Outpatients were included if they were at least 18 years of age, had a history of a penicillin allergy with reactions including anaphylaxis greater than 10 years ago, urticaria, swelling, and unknown, and a physician’s referral for an outpatient PST. Patients were excluded if they had a prior PST or reaction of anaphylaxis to penicillin within the prior 10 years. The primary outcome was the percentage of patients who successfully passed the three components of the penicillin allergy test and subsequently de-labeled penicillin allergy. Secondary outcomes included percentage of patients who received appropriate antibiotics following allergy de-labeling, incidence and type of IgE mediated penicillin allergic reactions, average reimbursement per patient, and average appointment time. Facility billing was conducted using ICD-10 codes, Z88.0: allergy status to penicillin and T36.0X5D: adverse effect of penicillins, subsequent encounter, and two CPT codes, 95018: percutaneous and injection allergy test drug/biologics and 95076: ingestion challenge initial 120 minutes.

A total of 457 outpatients received penicillin allergy testing during the study period. Physician specialties who referred patients were orthopedics, obstetrician-gynecologists, infectious disease, urology, urogynecology, cardiothoracic surgeons, and primary care providers. For the primary outcome, 439 patients (96.06%) were successfully de-labeled. All de-labeled patients received appropriate antibiotics following testing. There were 17 patients who developed minor itching with or without a localized rash following the amoxicillin, and one patient had a delayed reaction of rash 12 hours after the amoxicillin that resolved with an antihistamine. One patient had their penicillin allergy re-labeled. The average reimbursement was $423 per patient with the average appointment lasting 96 minutes.

This study supports the pharmacist as the provider in de-labeling penicillin allergies and improving patient health outcomes. Furthermore, given the availability of having a dedicated pharmacist, providers could refer multiple patients and expect a reasonable turnaround time to complete testing, including same day testing. Pharmacists, in collaboration with anesthesiologists and multiple physician specialties, successfully implemented an outpatient penicillin allergy testing service to safely de-label patients and support antimicrobial stewardship. The implementation of the clinic resulted in the approval of a full-time infectious disease pharmacist to run and expand the penicillin allergy testing service for the organization.