Reliability of early and late testing for suspected perioperative hypersensitivity.

Background The optimal timing of diagnostic testing for perioperative hypersensitivity (POH) remains unknown. It has been recommended that investigation is best carried out at least 4-6 weeks post event. On the other hand, guidelines dissuade the use of in-vitro tests later than 3 years post index reaction. Objective The purpose of this retrospective study is dual. First, it aims to assess the reliability of early and late skin tests (ST). Second, to verify whether dissuading late ex vivo/in vitro tests is substantiated. Methods For the first aim, patients were stratified over three time epochs. An early timing group, with investigations performed within 6 weeks; a recommended timing group, with tests performed between 6 weeks and 6 months; a late timing group, tested later than 6 months post event, respectively. For the second study purpose, we studied the reliability of sIgE-quantification and BAT rocuronium within 6 weeks and after three years in patients who experienced a ST-proven POH to rocuronium. Results 677 patients were included. Based on a positive ST result, a causative agent was found in 74.2% of the early timing group, in 62.6% of the recommended timing group and in 50% of the late timing group. A positive sIgE for rocuronium or morphine was found in 80% of patients tested within 6 weeks, in 63% of patients tested between 6 weeks and 3 years, and 50% of patients tested more than 3 years post event. A positive BAT was found in 83.3%, 51% and 20% of patients respectively. Conclusion Our data confirm that drug allergy evaluation for suspected POH can be performed before 6 weeks post event and there is no maximal upper time limit disclosing ex-vivo and in-vitro testing.