Basophil activation test shows poor sensitivity in immediate amoxicillin allergy

Published: November 16, 2022

The overwhelming proportion of patients with unverified, self-reported penicillin allergy can accomplish negative skin testing and then tolerate penicillin challenge without allergic reaction. The diagnosis of immediate hypersensitivity reaction can also be assessed using serum specific IgE testing; however, this suffers from suboptimal sensitivity. The Basophil activation test (BAT) has been suggested as a potentially useful assay to confirm or rule out allergy to penicillin or penicillin-like drugs; however, its diagnostic utility is uncertain.

A study recently published in The Journal of Allergy and Clinical Immunology: In Practice by Heremans et al., investigated the reliability of the BAT to amoxicillin, to determine whether BAT merits a role in routine assessment of immediate hypersensitivity to amoxicillin. BAT for amoxicillin was performed in 70 exposed control individuals and 66 patients diagnosed according to the European Academy of Allergy and Clinical Immunology guidelines for amoxicillin allergy. Upregulation of both CD63 and CD203c was flow-cytometrically assessed.

Despite analyses to reveal the BAT being discriminative between patients and exposed control individuals, sensitivity and specificity for CD63 upregulation were only 13% and 100%, respectively, and for CD203c upregulation, only 23% and 98%.

This study demonstrated that BAT with dual analysis of CD63 and CD203c performed poorly. The low sensitivity implies BAT is not useful as a routine test to establish or rule out a diagnosis of amoxicillin allergy.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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