Recurrent anaphylaxis highlighting methodological variability and diagnostic challenges in the basophil activation test: a case report

Background The basophil activation test (BAT) is an adjunct in identifying causative agents of anaphylaxis. However, its limited sensitivity and methodological variability may lead to inaccurate allergen identification. Case presentation A 74-year-old woman developed anaphylaxis during anesthetic induction. BAT performed 1 week after the anaphylaxis was negative at 1-hour incubation, whereas 24-hour incubation showed slight increase in basophil activation rates with propofol (7.9%), levobupivacaine (6.1%), with cefazolin remaining negative (0.2%). At the second surgery, propofol and levobupivacaine were avoided, whereas cefazolin was re-administered, resulting in recurrent anaphylaxis. Subsequent skin testing performed 6 weeks after the second anaphylaxis was positive for cefazolin. BAT performed with a 15-minute incubation using higher drug concentrations was also positive for cefazolin (14.3%). Conclusions Early testing after anaphylaxis, prolonged incubation, and suboptimal drug concentrations may compromise the accuracy of BAT results. This case underscores that methodological standardization and careful interpretation are essential for reliable BAT results.