Randomized Evaluation of Ten Allergy Skin Prick Test Devices

The goal of this study is to compare ten current and readily available FDA approved allergy skin prick devices to determine the most sensitive and specific product and methods used for the diagnosis of allergic disease. The primary outcome will be to determine the analytical sensitivity and specificity of all ten skin prick devices by measuring wheal and flare response to histamine and control diluent in 1mm increments. Secondary outcomes include comparison of skin prick technique, optimum histamine concentration, patient comfort, reproducibility, and the comparability of high-resolution digital images.

Neither the subject nor the technician are masked as to which device is being placed. However, the investigator who reads the skin prick test results is blinded as to which device is which.

Compare Wheal response among devices using 1mm precision. SPT test will be read at 15 min time point. The maximum wheal diameter will be recorded for each of ten skin prick devices. 3mm (and 2mm above negative control) qualify as a positive test.

Sensitivity is calculated by dividing the true positive wheals divided by true positives plus false negatives and multiplying by 100. For example one false negative out of 24 tests equals a sensitivity of 95.8%.

Compare 1mg/ml versus 6mg/ml histamine base for Duotip II twist method. Maximum wheal diameter is measured for each concentration.

Inclusion Criteria: Adults aged 18-65 with or without allergic disease Exclusion Criteria: severe concurrent illness uncontrolled asthma extensive eczema urticaria dermatographism pregnancy those taking antihistamines within the previous 10 days topical steroids immunomodulatory drugs long term use of oral steroids