Original article Flow-assisted diagnostic management of anaphylaxis from rocuronium bromide Diagnosis of anaphylaxis from neuromuscular blocking agents (NMBA) is not always straightforward. Therefore, additional reliable diagnostic tools are of tremendous interest. Currently three studies have assessed flow-assisted diagnosis of allergy from NMBA (1–3), and it appears that the technique constitutes a promising instrument for the diagnosis of hypersensitivity from NMBA. However, additional comprehensive studies are mandatory to fur- ther validate the activated basophils (BAT) and allow its entrance in mainstream application [review: (4), Ebo DG et al. unpublished data]. This study assesses the BAT in the diagnosis of anaphylaxis from rocuronium and evaluates whether the BAT could provide an instrument to identify cross- reactive NMBA and to tailor individual safe neuromus- cular blocking regimens. Methods Study population Fourteen patients who had presented hypotension and/or bron- chospasm within 5 min after injection of rocuronium demonstrating a positive ST for the drug were enrolled. Possible alternative causes (e.g. latex, chlorhexidine, antibiotics, analgesics and hypnotics) were excluded as described in (5). Eight individuals had tolerated rocuronium and demonstrated a negative ST served as a control group (C1). Basophil activation and ST were performed between 6 weeks and 3.5 years after the acute reaction. To confirm 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 anaphy- laxis from rocuronium. The technique also allows quick and simultaneous testing of different potential cross-reactive NMBA and to tailor a safe alternative. D. G. Ebo, C. H. Bridts, M. M. Hagendorens, C. H. Mertens, L. S. De Clerck, W. J. Stevens Department of Immunology, Allergology and Rheumatology, University of Antwerp, Antwerp, Belgium Key words: anaphylaxis; basophil activation test; cross- reactivity; flow cytometry; neuromuscular blocking agents. Prof. Dr W. Stevens Department of Immunologie, Allergologie and Rheumatologie Universiteit Antwerpen Campus Drie Eiken Universiteitsplein 1 2610 Antwerpen (Wilrijk) Belgium Accepted for publication 26 January 2006 Allergy 2006: 61: 935–939 Copyright Ó Blackwell Munksgaard 2006 ALLERGY DOI: 10.1111/j.1398-9995.2006.01094.x 935