Submitting/Presenting Author

Jordan Pitt, Children's Mercy HospitalFollow

Presenter Status

Fellow

Abstract Type

Research

Primary Mentor

Salman Aljubran

Start Date

5-5-2022 11:30 AM

End Date

5-5-2022 1:30 PM

Presentation Type

Poster Presentation

Description

Background: A refractory period of falsely negative testing can occur following a systemic allergic reaction to Hymenoptera sting. As a result, blood specific IgE and/or skin prick tests (SPT) for other allergens are often delayed.

Objectives/Goal: This study aims to identify the proportion of patients with falsely negative test results in the 6 weeks following an allergic reaction to food, and factors that may affect it.

Methods/Design: This is a retrospective chart review study. One hundred fourteen pediatric subjects met inclusion criteria. Each had a convincing history of food allergy with a systemic allergic reaction and was tested to the culprit food within 6 weeks. The proportion of negative tests for each testing modality was compared. Subjects testing negative were also compared to those testing positive. Chi-square and Fisher’s exact tests identified differences between groups.

Results: Seventeen of 79 blood IgE tests (21.5%) and 6 of 35 SPT (17.1%) were negative, with no significant difference between the two tests (p-value 0.591). The distribution of trigger foods was significantly different in subjects with negative versus positive tests. Importantly, there were no subjects who tested falsely negative to tree nuts out of the 38 blood IgE tests and 13 SPT for tree nut allergy.

Conclusions: The proportion of falsely negative tests in the 6 weeks following systemic allergic reactions to food is similarly low in both testing modalities. This proportion was even lower in subjects with tree nut allergy. Thus, testing can be considered to confirm food allergy in most patients with a convincing history during the weeks following a systemic reaction.

MeSH Keywords

Food Hypersensitivity

Included in

Pediatrics Commons

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May 5th, 11:30 AM May 5th, 1:30 PM

Timing Of Testing For IgE-mediated Food Allergy After Systemic Reaction

Background: A refractory period of falsely negative testing can occur following a systemic allergic reaction to Hymenoptera sting. As a result, blood specific IgE and/or skin prick tests (SPT) for other allergens are often delayed.

Objectives/Goal: This study aims to identify the proportion of patients with falsely negative test results in the 6 weeks following an allergic reaction to food, and factors that may affect it.

Methods/Design: This is a retrospective chart review study. One hundred fourteen pediatric subjects met inclusion criteria. Each had a convincing history of food allergy with a systemic allergic reaction and was tested to the culprit food within 6 weeks. The proportion of negative tests for each testing modality was compared. Subjects testing negative were also compared to those testing positive. Chi-square and Fisher’s exact tests identified differences between groups.

Results: Seventeen of 79 blood IgE tests (21.5%) and 6 of 35 SPT (17.1%) were negative, with no significant difference between the two tests (p-value 0.591). The distribution of trigger foods was significantly different in subjects with negative versus positive tests. Importantly, there were no subjects who tested falsely negative to tree nuts out of the 38 blood IgE tests and 13 SPT for tree nut allergy.

Conclusions: The proportion of falsely negative tests in the 6 weeks following systemic allergic reactions to food is similarly low in both testing modalities. This proportion was even lower in subjects with tree nut allergy. Thus, testing can be considered to confirm food allergy in most patients with a convincing history during the weeks following a systemic reaction.

 

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