Objective was to study and compare the parameters of the specificity and sensitivity of skin testing and serologic determination of specific cat and dog IgE. 88 patients with allergic rhinitis and / or asthma were examined by three different methods of specific allergic diagnosis (in vivo and in vitro) in accordance with the guidelines of the ethics committee of the National Pirogov memorial medical university, all were beyond the acute period. The inclusion criteria were allergic rhinitis diagnosis (both intermittent and persistent) and \ or asthma. Skin prick test was carried out according to the classical testing procedure in accordance with regulatory documents with commercial extracts of allergens. Western blot testing for specific IgE levels was performed using RIDA qLine test systems (R-Biopharm AG, Darmstadt, Germany) and Euroline (Euroimmun). The sIgE concentration was converted to a nominal scale (grades) according to the following rules: < 0.35 IU mL-1-level 0 (negative), (0.36-0.69) IU mL-1-level 1 (boundary levels ), (0.7- 3.49) IU mL-1-level 2 (slightly elevated), (3.50-17.4) IU mL-1-level 3 (moderately elevated), (17.5-49 , 9) IU mL-1-level 4 (high levels), (50-100) IU mL-1-level 5 (very high levels) and > 100 IU mL-1-level 6 (extremely high levels). Thus, the results of the two systems for the determination of specific IgE for dog allergen by the Rida AllergyScreen and Euroline methods do not agree very well due to the systematic divergence of indicators; the results of the two systems for the determination of specific IgE for cat allergen by the Rida AllergyScreen and Euroline methods agree very well. There is excellent agreement between the skin test with cat allergen and the detection of specific IgE by the Rida AllergyScreen test, between the skin test with cat allergen and the detection of specific IgE by the Euroline method. There is good agreement between the skin test with dog wool allergens and the detection of specific IgE by the Rida AllergyScreen test, between the skin test with dog hair allergen and the detection of specific IgE by the Euroline method there is satisfactory agreement. The systematic error of the measurement results between two in vitro tests for cat allergen was 0.1 ku/l, which indicates the presence of a small systematic difference, the systematic error of the measurement results between two in vitro tests for dog allergen was 0,26 ku/l, which indicates the presence of a moderate systematic difference.