Allergic skin testing: A clinical investigation

Forty patients were administered a total of 2,395 skin tests in order to assess the effects of method, concentration, diluent, manufacturer, and mixtures on patient reaction to inhalant extract solutions. The prick method was found to be superior to the scratch method. The intracutaneous technique exhibited the greatest degree of specificity. Patients reacted at a higher level to higher concentrations of extract solution, descending to a lower level of reaction to lesser concentrations of extract solution. Patient reactions were variable to aqueous vs glycerin solutions. Clear differences in the potency of extract solutions produced by manufacturers A, B, and C were evident. Specifically, the products of manufacturer C were least potent. The results illustrate the possibility of a dilution factor existing in mixtures of extract solutions, producing a decrease in their potency when compared to the potency of their individually administered components. A technique with the potential for wide acceptance and clinical applicability is proposed.