Evaluation of three methods for using the Duotip-Test device for skin testing

The sensitivity and precision of rotation, prick and puncture methods of using the Duotip-Test for epicutaneous allergy skin testing were evaluated. Forty-one volunteers who had not taken any antihistamines within the previous two weeks were recruited. The mean age was 21.6 years (range 18 to 25 years). Histamine hydrochloride 1 mg/ml and 50% glycerol saline were used as positive and negative controls, respectively. Each method of testing was performed in triplicate on the volar surface of both forearms. Wheal and flare were measured 15 minutes later. Rotation, prick and puncture methods produced histamine mean wheal diameter +/- standard deviation of 6.61 +/- 0.87 mm, 3.86 +/- 1.03 mm, and 3.00 +/- 0.65 mm, respectively (p < 0.01). The coefficient of variation of rotation method was 13.13%. It was the only method that gave coefficient of variation lower than 20%. False negative and false positive proportions of rotation method using a 4 mm criterion for positive reaction were 1.5% and 0.75%, respectively. Rotation method was well accepted by the volunteers although it was ranked highest in pain. We concluded that the rotation method of using Duotip-Test is a highly reliable technique for skin testing.