The allergy pricker. Qualitative aspects of skin prick testing using a precision needle.

Skin prick test has advantages over other diagnostic tests in allergy, and attempts to increase the reproducibility are warranted. A standardised disposable precision needle with a needle point of 1.0 mm has recently become available. Based on 960 tests with histamine and grass pollen (Phleum pratense) the reproducibility of the skin prick weal area was calculated. Using histamine 10 mg/ml and grass pollen (1000 and 5000 PNU) a significantly lower coefficient of variation was found compared with a standard blood lancet with a point of 4 mm. The mean weal reaction is reduced to about 80% of the size obtained with the blood lancet. Testing with the precision needle resulted in a significantly reduced incidence of bleedings. The precision needle simplifies the skin test and does not require as much skill as other needles, and is recommended for both routine tests and the biological standardization of allergen extracts.