Wasp venom allergy can trigger severe allergic reactions, and predicting these acute responses remains challenging. This study evaluates the utility of immune system indexes, particularly the eosinophil-basophil/lymphocyte (EBLR) and eosinophil-basophil-platelet/lymphocyte (EBP/L) ratios, in assessing the severity of allergic reactions in patients with wasp venom allergy. A total of 61 patients with confirmed wasp venom allergy were categorized according to the Mueller scale, which classifies the severity of allergic reactions. Blood samples were analyzed for total and specific IgE levels, alongside a range of hematological and biochemical parameters. The study found significant differences in the EBLR and EBP/L indexes between patients with mild (Mueller I-II) and severe (Mueller III-IV) allergic reactions, with higher values indicating more severe responses. However, no significant differences were observed in other immune indexes, such as PLR, NLR, SII, and SIRI, or in additional blood parameters. These findings suggest that the EBLR and EBP/L ratios may serve as useful markers for predicting the severity of allergic re-actions in patients with wasp venom allergy. This is the first study to establish such a link, alt-hough further research with larger cohorts is necessary to confirm these results and their poten-tial application in clinical settings.