Repeatability and Reproducibility of Skin Test Endpoint Titration

Study Overview
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Brief Summary
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This study will examine the within-tester repeatability and between-tester reproducibility of skin test endpoint titrations performed in those with allergic sensitivities.

Detailed Description
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Participants will be recruited from the local community. Participants with a previous history of skin prick testing in our lab will not be required to undergo preliminary skin prick testing, as the allergen to be used for skin prick titrations is known. New participants will undergo skin prick testing. The procedures for skin prick testing and skin test endpoint (STE) titration will be guided by the AllerGen CIC Allergen Skin Titration by Epicutaneous Method (Prick) Standard Operating Procedure. Different allergen extracts for the skin prick test or different doubling doses of an allergen in duplicate for the STE will be applied to the forearm, pricked with a lancet, and assessed ten minutes later by measuring the wheal sizes produced. The study will require three visits to the lab (i.e. three testers), each separated by one week and lasting roughly 30 minutes. Each visit will entail the duplicate STE procedure performed by a different tester. If a participant is new to the lab, they will undergo skin prick testing during their first lab visit prior to undergoing the skin prick titration and so, their first study visit may last up to one hour.

Official Title
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Within-tester Repeatability and Between-tester Reproducibility of Skin Test Endpoint Titration

Conditions
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Allergic Reaction

Intervention / Treatment
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* Procedure: Skin test endpoint titration


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: must have allergic sensitivities confirmed by a skin prick test (or historically) to at least one of the study allergens Exclusion Criteria: skin condition on the forearms if there is a situation where interpretation of skin reactions would be difficult (e.g. sleeve tattoos, scarring) regular use of anti-histamines (assessed on a case-by-case basis)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Subjects<br>Each subject will undergo skin test endpoint titrations with three different testers. | Procedure: Skin test endpoint titration<br>* An allergen that is suitable to cause skin reactions when introduced to the forearm through pricking will be administered in doubling concentrations.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Within-tester repeatability | Comparison of wheal size (in mm) of skin reactions caused by a tester (duplicate skin pricking for each concentration of allergen administered) | 10 minutes post skin pricking | 
| Between-tester reproducibility | Comparison of wheal size (in mm) of skin reactions caused by three different testers | approximately 3 weeks (one week washout between tests) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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skin test endpoint