Department of Allergy and Allergy Research Center, Pediatric Hospital "P&A Kiriakou", National and Kapodistrian University of Athens, Athens, Greece.
Int Arch Allergy Immunol. 2010;151(4):343-5. doi: 10.1159/000250443. Epub 2009 Oct 22.
Mean diameter or longest diameter are the 2 most frequently used parameters for wheal response assessment after skin prick testing (SPT). We aimed to compare these 2 parameters taking as gold standard the surface of the wheal skin response.
Patients suspected of having an allergic reaction against inhalant allergens have been skin prick tested using the Pan-European GA(2)LEN SPT panel. Fifteen minutes later, macroscopically evident wheal and flare reactions were marked with a pen and transferred to paper with a transparent scotch tape. Each paper-transferred wheal was scanned with an ordinary scanner, and its surface-corresponding maximum perpendicular diameters and longest diameters were measured using a computer software application for image recognition, developed for this purpose. Correlation coefficients (Spearman's rho) between surfaces and respective mean (rho(mean)) or longest (rho(longest)) diameters were calculated and subsequently compared.
1,554 SPTs were performed in 74 patients. In 264, a macroscopically evident wheal and flare response was observed. Both mean and longest diameters correlated significantly with the wheal surfaces. However, rho(longest) was statistically significantly larger than rho(mean) when the surface of the wheal was >17 mm(2) (rho(longest) > 0.860 vs. rho(mean) < 0.660; p < 0.05).Such a surface corresponds to a maximum diameter of approximately 7 mm and a mean diameter of approximately 6 mm. Thus, the larger the surface of the wheal, the more appropriate the usage of the longest diameter.
The longest wheal diameter alone seems to be a better surrogate marker of the wheal surface in comparison with the mean diameter. In addition, it is easier and faster to measure. Therefore, we propose this as the optimal methodology to evaluate SPTs.
在皮试（SPT）后评估风团反应，平均直径或最长直径是最常使用的 2 个参数。我们旨在以风团皮肤反应的表面作为金标准来比较这 2 个参数。
怀疑对吸入性过敏原过敏的患者已使用泛欧 GA(2)LEN SPT 面板进行皮肤点刺测试。15 分钟后，用钢笔标记明显的风团和红晕反应，并将其转移到带有透明胶带的纸上。使用为此目的开发的图像识别计算机软件应用程序，扫描每个转移到纸上的风团，并测量其表面对应的最大垂直直径和最长直径。计算表面与各自平均（rho(mean)）或最长（rho(longest)）直径之间的相关系数（Spearman rho），并随后进行比较。
在 74 名患者中进行了 1554 次 SPT。在 264 次中，观察到明显的风团和红晕反应。平均直径和最长直径与风团表面均显著相关。然而，当风团表面 >17mm² 时，rho(longest)明显大于 rho(mean)（rho(longest) > 0.860 与 rho(mean) < 0.660；p < 0.05）。这样的表面对应于最大直径约为 7mm 和平均直径约为 6mm。因此，风团的表面越大，最长直径的使用就越合适。
与平均直径相比，最长风团直径似乎是风团表面的更好替代标志物。此外，测量起来更容易、更快。因此，我们建议将其作为评估 SPT 的最佳方法。
