Mismatch Identified Between Penicillin Allergy Test Results, Primary Care Allergy Labels


These findings are relevant given that if labels are incorrectly identified, those with allergies may be at risk of severe reactions or receive suboptimal treatment.

There is a substantial mismatch between the results of penicillin allergy tests and allergy labels in primary care, according to new findings, with a smaller mismatch between test results and the hospital allergy labels.1

These findings are significant, given that if allergies are incorrectly disproved, patients may get suboptimal treatment, longer admissions to hospitals, and increased antibiotic-resistant infection risk.

As much as 50% of patients are estimated to have inaccurate penicillin allergy labels in electronic medical records after investigations into penicillin allergy.2 Given this background, this study was authored by Sara Fransson, from the Department of Dermatology and Allergy at Copenhagen University Hospital – Herlev and Gentofte in Denmark.

“The primary aim of this study was to investigate the degree of match/mismatch between penicillin allergy labels in hospital and primary care EMR systems in patients who had undergone penicillin allergy investigation in a hospital allergy clinic,” Fransson and colleagues wrote.

Background and Findings

The investigators sought to evaluate the consistency of penicillin allergy labels between hospital and primary care electronic medical record systems in patients who underwent penicillin allergy investigations.

The research team’s secondary objective was to examine the associations between various factors—such as sex, type of reaction, age, general practitioner changes, and allergy investigation results—and the mismatch of labels.

The team used participants aged 18 years and above who were tested for allergies to penicillin at the Allergy Clinic, Gentofte Hospital between 2017 - 2019. Drug provocation tests were done utilizing different penicillin types, and the results were recorded in the hospital’s electronic medical records.

Data on admissions, allergy labels, and current general practitioners were gathered from individual EMRs. Standardized communication and formats for discharge letters and allergy labels in primary care were found to be lacking.

The investigators sent a letter explaining the study protocol to GP clinics, and data was gathered through phone calls or secure emails. Allergy labels were considered to be a match if the third anatomical therapeutic chemical classification level matched, indicating any type of penicillin allergy registration in the records.

A logistic regression analysis was done to identify factors associated with the mismatch between testing results and GP clinic labels. Statistical significance was set at P < .05.

Overall, the investigators were able to identify a total of 849 individuals from 390 different GP clinics. After excluding 41 patients from 14 GP clinics due to reasons like emigration or death, data was obtained for 60% of the participants from 255 clinics.

The median age at drug provocation test was 50 years, with a range identified of 37 - 63. Among the participants, 15.1% were found to have had confirmed penicillin allergy, while 84.9% had their penicillin allergy disproved. Confirmation rates for penicillin allergy were found to be 9% for males and 17% for females.

In the study, the research team reported that 26.0% of those with confirmed penicillin allergy were found not to have an allergy label in their primary care records, while 21.4% of patients with disproved allergy still had an incorrect label.

The odds of having a mismatch in the GP clinic were also found to be lower for males and for those with 3 or more admissions to hospitals since allergy testing. Sex, index reaction type, age, results of drug provocation test, GP changes, and number of GPs in the GP clinic did not show any association with the mismatch.

“Improvements in communication between health care sectors are necessary,” they wrote. “Follow-up phone calls, involvement of community pharmacists or drug allergy passports have been suggested to improve communication.”


  1. Fransson, S, Boel, JB, Holm, A, et al. Inconsistencies in penicillin allergy labels in hospital and primary care after allergy investigation. Clin Exp Allergy. 2023; 00: 1- 4. doi:10.1111/cea.14347.
  2. Lachover-Roth I, Sharon S, Rosman Y, Meir-Shafrir K, Confino-Cohen R. Long-term follow-up after penicillin allergy delabeling in ambulatory patients. J Allergy Clin Immunol Pract. 2019; 7(1): 231- 235.e1. doi:10.1016/j.jaip.2018.04.042.
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