Comparison of intradermal allergy test and enzyme-linked immunosorbent assay in dogs with allergic skin disease

Abstract

Results of an ELISA for allergen-specific IgE were compared with results of an intradermal (ID) allergy test in 5 clinically normal dogs and 36 dogs referred for evaluation of allergic dermatitis. The ELISA had a sensitivity of 100% and a specificity of 0%. Agreement between ID allergy test and ELISA for positive and negative results ranged from 44 to 56% for pollens, 39% for house dust/dust mite, 22% for fungi, and 54% for fleas. Agreement between ID allergy test and ELISA scores for all pollens was only 10% greater than that expected by chance alone, and a kappa value of 0.17 confirmed poor test agreement. The greatest disparity in results was seen in dogs with negative ID and positive ELISA results. Median ELISA absorbance values for 15 groups of related allergens were compared in 4 groups of dogs: clinically normal dogs, atopic dogs with positive ID reactivity, suspected atopic dogs with negative ID reactivity, and flea-allergic dogs. There was no significant difference in median ELISA values between clinically normal dogs and flea-allergic dogs, or clinically normal dogs and atopic dogs for any allergen group. Although the ELISA absorbance value for fungal antigens was significantly higher in dogs suspected of being atopic than in clinically normal dogs, there was no significant difference in median ELISA values for any other allergen group. These findings suggested the disparity between ID allergy test and ELISA results was primarily attributable to false-positive ELISA reactions rather than greater ELISA sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)