COMPARISON OF WHEAL SIZE INDUCED BY BIFURCATED NEEDLE^® AND SMARTPRACTICE^® PRICK LANCET

<p>Background: There is reportedly a difference in the diameter of the skin reaction induced by different types of skin prick test (SPT) devices. We compared the SPT diagnostic accuracy and wheal size between a Bifurcated Needle^® (BN) and SmartPractice^® Prick Lancet (PL), which are commercially available in Japan.</p><p>Methods: An SPT was performed on 15 adults with and 10 without subjective symptoms of cedar pollinosis who wished to be examined for Japanese cedar pollen (JCP) sensitization. The SPT was performed blindly with a BN or PL with 10mg/ml of histamine dihydrochloride, 50% glycerosaline control, and JCP extract solution (TORII PHARMACEUTICAL CO., LTD., Tokyo, Japan). The wheal sizes induced by the BN and PL were then compared. The JCP-specific IgE antibody titer was measured to compare the sensitivity and specificity of the SPT.</p><p>Results: Histamine wheal diameters were 6.0 (5.5-6.5) mm by BN and 6.0 (5.5-6.5) mm by PL (p=0.67), and none of the negative control solutions induced wheal. The respective sensitivity and specificity for cedar sensitization were 100% and 86% for BN, 100% and 79% for PL, and the areas under the ROC curve were 0.72 and 0.69 (p=0.32).</p><p>Conclusion: The diagnostic accuracy of cedar pollen extract based on specific IgE-JCP sensitization and the diameter of the wheal produced by a BN and PL were considered equivalent.</p>