Performance and Pain Tolerability of Current Diagnostic Allergy Skin Prick Test Devices

Abstract

Allergen skin prick testing remains an essential tool for diagnosing atopic disease and guiding treatment. Sensitivity needs to be defined for newly introduced devices. Our aim was to compare the performance of 10 current allergy skin prick test devices. Single- and multiheaded skin test devices (n = 10) were applied by a single operator in a prospective randomized manner. Histamine (1 and 6 mg/mL) and control diluent were introduced at 6 randomized locations onto the upper and lower arms of healthy subjects. Wheal and flare reactions were measured independently by 2 masked technicians. Twenty-four subjects provided consent, and 768 skin tests were placed. Mean wheal diameter among devices differed from 3.0 mm (ComforTen; Hollister-Stier, Spokane, Wash) to 6.8 mm (UniTest PC; Lincoln Diagnostics, Decatur, Ill) using 1 mg/mL histamine (P < .001) and 4.8 mm (GREER Pick; Greer, Lenoir, NC) to 8.4 mm (Duotip-Test II; Lincoln Diagnostics, Decatur, Ill; and Sharp-Test; Panatrex, Placentia, Calif) using 6 mg/mL histamine (P < .001). The false-negative rates ranged from 0% to 45% with 1 mg/mL histamine. The analytical specificity was 100% for all devices tested. All devices were well tolerated, with average pain score of less than 4 on a 10-point visual analog scale. Pain scores were higher among women, but this did not reach statistical significance. The Multi-Test PC and the UniTest PC had the lowest pain scores compared with the other devices. All 10 skin prick test devices displayed good analytical sensitivity and specificity; however, 3 mm cannot arbitrarily be used as a positive threshold. The use of histamine at 1 mg/mL is unacceptable for certain devices but may be preferable for the most sensitive devices. On average, there was no pain score difference between multiheaded and single-head devices.