Flow-assisted diagnostic management of anaphylaxis from rocuronium bromide

Background: Diagnosis of anaphylaxis from neuromuscular blocking agents (NMBA) is not always straightforward. Objectives: To assess flow cytometric analysis of activated basophils (BAT) as a diagnostic instrument in anaphylaxis from rocuronium. To investigate whether the technique might help to identify cross-reactive and safe alternative compounds. Methods: For validation of the BAT, 14 patients with perioperative anaphylaxis demonstrating a positive skin test (ST) for rocuronium and eight individuals that tolerated rocuronium and a negative ST for this drug were enrolled. To confirm specificity of the BAT, five patients that tolerated atracurium or cisatracurium with a negative ST for rocuronium were tested. Basophil activation with rocuronium, vecuronium, atracurium, cisatracurium and suxamethonium was analysed flow cytometrically by labelling with anti-CD123/anti-HLADR/anti-CD63. Results: Sensitivity of BAT for rocuronium was 91.7% and specificity 100%. However, in two patients the BAT was lost as a diagnostic tool, as their cells were nonresponsive to positive control stimulation and allergen. Seven from the 12 responsive patients also demonstrated a clear basophilic activation for vecuronium. Moreover, according to ST and/or BAT cross-reactivity between rocuronium and vecuronium was suspected in 10/14 patients. Except one patient, all patients had negative BAT and ST investigations for atracurium and cisatracurium. Currently, five patients tolerated administration of cisatracurium. All control individuals demonstrated negative ST and BAT for all tested NMBA. Conclusions: The BAT constitutes a reliable instrument to diagnose anaphylaxis from rocuronium. The technique also allows quick and simultaneous testing of different potential cross-reactive NMBA and to tailor a safe alternative.