Pijnenborg H, Nilsson L, Dreborg S
Medical Faculty, University of Limburg, Maastricht, The Netherlands.
Allergy. 1996 Nov;51(11):782-8.
We evaluated a new method of computer-based scanning of skin prick test wheal areas. To test the calibration of the program, we scanned five constructed circles of exactly defined areas between 5 and 255 mm2. One of these circles was scanned in different degrees of contrast (modes), the middle mode being used in the other experiments. We also investigated the inter- and intraoperator variation. Finally, results obtained by measuring diameters of wheals and by the new method of area determination were compared for 82 histamine and 75 egg wheals. The areas found agreed well with the real areas (P < 0.01) (mean 97.4-100.8%), except for the smallest wheal (5mm2) (NS). Areas obtained in the "middle position" closely resembled the real area. The intraoperator coefficient of variation (c.v.) was 1.4% (0.3-4.3), the day-to-day c.v. was 1.9% (0.2-5.3), and the interoperator c.v. was 2.3% (0.7-5.7), with a higher c.v. for small areas. Histamine and egg wheals were significantly larger with the diameter method (126% and 129%, respectively) than with the area method. The difference between the methods was most pronounced for small wheal areas. The c.v. of the scanning method was significantly lower than that of the diameter method. The new program was precise and is recommended for registration of skin test reactions in scientific trials. Although the scanner works well and has high precision, the major problem in skin testing seems still to be the reproducibility of the skin test technique employed.
我们评估了一种基于计算机扫描皮肤点刺试验风团面积的新方法。为测试该程序的校准情况，我们扫描了五个面积精确界定在5至255平方毫米之间的人造圆圈。其中一个圆圈在不同对比度（模式）下进行扫描，其他实验采用中间模式。我们还研究了不同操作人员之间以及同一操作人员内部的差异。最后，对82个组胺风团和75个鸡蛋风团分别采用测量风团直径的方法和新的面积测定方法进行结果比较。除最小的风团（5平方毫米）外（无显著差异），所测得的面积与实际面积吻合良好（P<0.01）（平均为97.4 - 100.8%）。在“中间位置”获得的面积与实际面积非常相似。同一操作人员内部的变异系数（c.v.）为1.4%（0.3 - 4.3），每日变异系数为1.9%（0.2 - 5.3），不同操作人员之间的变异系数为2.3%（0.7 - 5.7），小面积的变异系数更高。采用直径法测得的组胺和鸡蛋风团明显大于面积法（分别为126%和129%）。两种方法之间的差异在小风团面积时最为明显。扫描法的变异系数显著低于直径法。该新程序精确，推荐用于科学试验中皮肤试验反应的记录。尽管扫描仪运行良好且精度高，但皮肤试验中主要问题似乎仍然是所采用皮肤试验技术的可重复性。
