This is a single-center, retrospective, observational study with 181 pregnant females between July 2019 to June 2021. Patients with reported penicillin allergy were referred to the BC Women’s Hospital Penicillin Allergy clinic in Vancouver, Canada and were included regardless of medical, surgical, or medication history. Self-reported allergy histories required for each tool were routinely collected prior to patients’ first clinic visit. Information was stored on REDCap. This cohort was included in previous studies investigating the safety of DOC in pregnant populations [9].
The primary outcome of this study was to assess reliability of the electronic decision support tool compared with allergist assessment. Allergist assessment and to either pursue IDT and gold standard of DOC were previously recorded. Allergy histories were applied to the electronic decision support tool and the risk categories decided by the clinical assessment of the electronic decision tool were compared with allergist assessment. Risk categories included: allergic, very low risk of allergy, possible allergy, not allergic. The secondary outcome was to compare our electronic decision support tool with other published assessment tools to identify low risk patients appropriate for DOC. Patients were risk stratified by each tool into high, intermediate, and low risk categories.
With our interest specifically to identify patients at lowest risk for penicillin allergy, we opted to categorize all patients in the low risk stratification tier of each tool as screen negative this included those scoring PENFAST = 0–2 (very low and low risk), JAMA = low risk, FIRSTLINE = very low risk. All remaining patients were considered test screen positive. All patients deemed very low risk by clinician judgment received DOC. All remaining patients received IDT with benzylpenicilloyl polylysine and penicillin G. Positive IDT is defined as 3 × 3 mm greater than the negative control or a wheal size > 5 mm with underlying erythema, interpreted at 15 minutes [10,11,12]. If IDT was negative, patients then proceeded to a DOC. All equivocal IDT and delayed skin rash were considered test positive. All equivocal DOC without specifiers of exact symptoms experienced by patients were considered test negative. Examples of delayed DOC were those with delayed rash or delayed emesis (Type 4 hypersensitivity). None of the equivocal reactions had documented symptoms.
The assessor was blinded to patient information during data analysis. Collection of our data as a prospective cohort had received institution ethics approval. The screening tool results were then compared to clinician judgement to IDT and DOC. Additional ethics and consent waiver from the University of British Columbia was obtained for utilizing the data for algorithm validation.
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