Background: Hypersensitivity to antibiotics is not always easy to assess. The basophil activation test with up-regulation of CD63 quantification is a new technique that might improve diagnostic accuracy. Objectives: the aim of the study was to determine the usefulness of flow cytometry in the diagnosis of β-lactam allergy, to investigate whether flow cytometry might help to identify cross-reactive and safe alternative antibiotics and to determine the adequate time interval between the allergic reaction and testing. Methods: A total of 58 patients with previous history suggestive for an immediate-type hypersensitivity caused by antibiotics were tested. We performed skin tests and the basophil activation test using up-regulation of CD63. Results: There was a fair agreement between the basophil activation test and positive history plus skin tests (0.35 when BAT was performed within two years and 0.25 after two years). There were significantly more frequent positive basophil activation tests within 2 years than after (30.76% vs. 7.69%, Fisher exact test, p=0.032). There were 5 patients with positive history, negative skin tests and a corresponding positive flow cytometry. Conclusion: The agreement between the basophil activation test and skin tests is fair, but their diagnostic values are complementary. Flow cytometry is particularly useful in patients with positive history and negative skin tests as potential dangerous provocation tests might be avoided. The diagnostic value of flowcytometry is increased when recent reactions are investigated.
Hagău N, Sfichi M, Bologa R, Cocu S, Indrei C, Alb I, et al. Basophil activation test using flow cytometry in the diagnostic of antibiotic allergy. Rev Romana Med Lab. 2010;18(4):47-53