Skin testing: a survey of allergists

Abstract

In the allergist's office, skin testing remains the central way to confirm allergic response. Although anecdotal data suggest widely varying practices in skin testing by allergists, the diversity and relative frequency of these practices have not been documented. To determine the extent of the diversity in skin testing practices among allergists. A questionnaire was sent via the Internet to all physician members and fellows of the American College of Allergy, Asthma and Immunology who practice in the United States. This survey explored choice of extract concentrations, skin test device, number and type of tests, method for interpretation and documentation of skin test results, and quality assurance procedures used. Overall, a significant degree of variability was reported with regard to number of skin tests performed, extract concentrations, skin test devices, interpretation and documentation of results, and quality assurance procedures. The average number of skin prick tests performed ranged from 5.09 (grasses) to 10.9 (trees), whereas the average number of intradermal tests performed ranged from 2.03 (grasses) to 5.6 (perennial). The allergen extract concentrations used for intradermal testing varied widely. Expressed as a dilution of the concentrated extracts, 20.8% use 1:100 dilutions, 10.3% use 1:500 dilutions, and 59.4% use 1:1,000 dilutions. Significant variability also occurred regarding devices and the technique with which the devices were used. Most clinicians (92.1%) used the most concentrated extract available for skin prick testing. For reporting the results of skin testing, 53.8% used a 0 to 4+ scale, and only 28.3% measured orthogonal diameters. Of those using a 0 to 4+ scale, two thirds related the results to the size of the histamine control. Quality assurance testing was reportedly performed by 61.2% of responders. However, less than 10% of responders used an objective test protocol for this purpose. This survey highlights some of the areas that allergists can improve on in the use and reporting of skin tests.