Patient perspectives on penicillin allergy and testing

Background: Most patients who report penicillin allergy are found to tolerate penicillin later in life. Few studies have examined patients' understanding and beliefs about penicillin allergy and testing. Evaluating patients' perspectives may help identify ways to improve patient education and increase testing to de-label those who can tolerate penicillin. Objective: To better understand patient perspectives on penicillin allergy testing and to identify whether patient characteristics and beliefs impact completion of testing. Methods: Patients who were visiting our allergy clinics and had documentation of a penicillin allergy in the electronic medical record (EMR) were approached to complete a survey with regard to their reaction history and knowledge and/or perspectives about penicillin allergy and testing. Eighty-eight patients completed the survey, and their medical records were reviewed to collect results of penicillin testing. Results: Fewer than half of the patients (45.5%) who had EMR-documented penicillin allergy reported awareness that testing for penicillin allergy is available. Awareness of penicillin allergy testing was significantly associated with completion of testing, whereas other patient characteristics, such as education, income, and distance to the hospital, were not. Patients who scheduled a return visit for testing at the time of their initial visit were significantly more likely to follow through with testing. Most patients were interested in penicillin testing. For patients who were not interested, the most frequently cited reason was fear of adverse effects of testing. Conclusion: Among the patients who carried a penicillin allergy label, those who were aware of penicillin allergy testing were more likely to complete testing, and ease of scheduling contributed to higher rates of testing completion. Fear about adverse effects from testing was the most reported barrier. Our findings emphasized the importance of increasing awareness of the availability and safety of penicillin testing through patient education and collaboration with other specialties.

A Continuing Education Activity Durably Addressed Knowledge Gaps Related to Penicillin Allergies Among Pharmacists and Pharmacy Technicians

Background: Penicillin allergy is one of the most frequent self-reported allergies; however, only about 10% of reported allergies are accurate. Objectives: Through the creation of a continuing pharmacy education (CPE) activity, we sought to assess knowledge gaps and comfort levels in the management of penicillin allergies. Methods: A 1-hour enduring-content CPE activity was offered as an interactive course from September 20, 2019, to September 20, 2020. Participants completed 3 surveys (pre-survey, post-survey, and follow-up survey). Participants were pharmacists and pharmacy technicians who completed, at a minimum, the activity and both pre- and post-surveys. The primary outcome was the percentage of participants scoring >80% on knowledge-based questions on the post-survey compared with the pre-survey. Secondary outcomes included pre-post comparisons on knowledge-based questions, participants’ self-report of an allergy, and comfort levels dispensing cephalosporins in a patient with a self-reported penicillin allergy. Results: A total of 389 participants completed the CPE activity, with 176 included for analysis. Significantly more participants scored >80% on knowledge-based questions on the post-survey compared with the pre-survey (71.6% vs 22.7%, P < .001). There was no significant difference between the percentage of participants scoring >80% on the post-survey and the follow-up survey (71.6% vs 65%, P = .119). The majority of participants (74%) felt comfortable dispensing a cephalosporin in a patient with a penicillin allergy on the pre-survey, with similar percentages on the post- and follow-up surveys (77% and 90%, respectively). Conclusion: A targeted continuing education program improved overall knowledge, which was sustained for up to 2 months.

Impact of Penicillin Allergy Label on Length of Stay and Mortality in Hospitalized Patients through a Clinical Administrative National Dataset

<b><i>Background:</i></b> Penicillin allergy is a common problem in the management of infectious diseases. The aim of this study was to determine the impact of penicillin allergy on length of hospital stay (LOHS) among hospitalized adult patients and on in-hospital mortality at a national level. <b><i>Methods:</i></b> A retrospective cohort study of adult patients discharged from the Spanish Hospital System between 2006 and 2015 was conducted using the Minimum Basic Data Set (MBDS). We compared LOHS and in-hospital mortality of adult patients whose records contained penicillin allergy code V14.0 (International Classification of Diseases, Ninth Revision, Clinical Modification) as a secondary diagnosis, with a random sample without such a code. <b><i>Results:</i></b> We identified 981,291 admissions with code V14.0, which corresponded to 2.63% of all hospitalizations. Adults patients with a penicillin allergy label were significantly older than patients without such a label, with a median of 70 years (interquartile range [IQR]: 51–80) versus 63 years (IQR: 40–77). The proportion of women and the prevalence of infectious diseases were higher in the group with a penicillin allergy label (61.40% vs. 53.84%; 34.04% vs. 30.01%; respectively). We found a higher median Elixhauser-Van Walraven score in hospitalized patients with an allergy label. The median LOHS for hospitalizations with a penicillin allergy label (5 [IQR: 2–9]) was significantly longer than that in those without such a label (4 [IQR: 2–9]). Multivariate analysis showed an increase in LOHS due to the penicillin allergy label (odds ratio [OR] [95% confidence interval [CI]: 1.061 [1.057–1.065]) and a decrease in mortality in penicillin allergy records (OR [95% CI]: 0.834 [0.825–0.844]). <b><i>Conclusion:</i></b> In our study, the prevalence of a penicillin allergy label in hospitalized patients, using the MBDS, is low. Hospitalizations with an allergy label was associated with a longer LOHS. However, penicillin-allergic patients did not show higher mortality rates. Inaccurate reporting of penicillin allergies may have an impact on healthcare resources.

Tackling penicillin allergy delabeling with ultra-sensitive in vitro test and human-like specific IgE standards

Background: Penicillin allergy delabeling initiatives are now part of antibiotic stewardship programs and include the use of invasive and risky in vivo tests. Instead, the quantification of specific IgE is highly useful to confirm immediate allergy to penicillins. However, discrepant results associated to the low sensitivity of the in vitro tests have limited their routine diagnostic use for delabeling purposes. We aimed to tackle a novel diagnostic strategy for specific IgE testing based on a homologous interpolation scheme, using recombinantly produced standards. Methods: Serum samples from a cohort of allergic patients and controls were analysed by a chemiluminescence-based immunoassay, using a bispecific binanobody as standard. The novel standard targets the major antigenic determinant of penicillin G and the paratope of Omalizumab, acting as human-like specific IgE. Results: Testing a cohort of 65 human serum samples, the method achieved a good agreement and strong positive relationship, reaching a limit of detection below 0.1 IU/mL. The sensitivity of the in vitro test significantly increased (66 %), doubling that of the ImmunoCAP reference in vitro assay with an overall specificity of 100 %. Conclusions: The new diagnostic strategy compares favourably with the results obtained on the ImmunoCAP system, paving the way towards the standardization of penicillin allergy testing. The recombinant standards are potent calibrators, highly stable, easy and inexpensive to produce, and overcome the limitation associated with preparations derived from pooled human serum, expediting the production of next generation standards with different specificities to successfully tackle β-lactam allergy delabeling by in vitro tests.