D1.224 - Clinical performance of IgE Quaternary Ammoniums, Atracurium, Rocuronium and Suxamethonium for the diagnosis of an allergy to curares

Allergy to neuromuscular blocking agents (NMBAs) is the leading cause of perioperative anaphylaxis, with rocuronium (Rocu) and suxamethonium (Suxa) being the most frequently implicated agents. Accurate allergy assessment is critical to confirm immediate drug hypersensitivity reactions (IDHR) and to prevent potentially fatal reactions upon re-exposure. However, the diagnostic performance of NMBA-specific IgE assays available in France has not yet been thoroughly established. 

This study aimed to evaluate the diagnostic performance of specific IgE assays for quaternary ammoniums (QA), atracurium (Atra), Rocu, and Suxa in diagnosing NMBA-induced IDHRs.

We included all adult patients at Nîmes University Hospital who experienced suspected perioperative anaphylaxis to NMBAs and underwent an allergy workup between February 2022 and December 2024. Specific IgE assays for QA, Atra, Rocu, and Suxa were performed using a fluoroenzymatic method (ImmunoCAP, ThermoFisher). Diagnosis was established based on a concordance between clinical history, tryptase kinetics, and skin test results. Diagnostic performance was analyzed using receiver operating characteristic (ROC) curves to determine optimal thresholds (So) along with sensitivity (Se) and specificity (Sp).

Among 50 patients included, NMBA allergy was confirmed in 20 cases (40%; 4 to Atra, 10 to Rocu, and 11 to Suxa). IgE levels for QA were significantly higher in patients allergic to Rocu (3.88 vs. 0.20 kU/L, p < 0.001) and Suxa (1.33 vs. 0.09 kU/L, p = 0.001) compared to non-allergic patients, but no significant difference was observed for Atra (p = 0.55). The area under the curve (AUC) values for IgE assays were 0.70 for Rocu (p = 0.07; So = 0.96 kU/L; Se = 40%; Sp = 96.6%), 0.72 for Suxa (p = 0.05; So = 0.31 kU/L; Se = 44.4%; Sp = 100%), and 0.60 for Atra (p = 0.51; So = 0.10 kU/L; Se = 25%; Sp = 96.43%).

Specific IgE assays for Rocuronium and Suxamethonium, in addition to IgE for Quaternary Ammoniums, demonstrate excellent specificity. These assays could enhance diagnostic accuracy and optimize the management of patients exposed to these NMBAs during anesthesia.