Basophil Activation Test Promising and Accurate Diagnostic Tool for Egg Allergy

A recent study published in the journal of Allergy And Clinical Immunology conducted by researchers at King's College London's School of Life Course Sciences suggests that the basophil activation test (BAT) is a highly accurate diagnostic tool for food allergies, specifically egg allergy. The findings challenge the conventional view that double-blind placebo-controlled food challenges (DBPCFC) are the gold standard for food allergy diagnosis. The study, known as the BAT 2 study, was led by Alexandra F. Santos, MD, PhD, from the Department of Women and Children's Health (Pediatric Allergy).

The researchers aimed to evaluate the diagnostic accuracy of the BAT compared to other tests commonly used to diagnose egg allergies, such as skin prick tests (SPT) and specific immunoglobulin E (sIgE) testing. They conducted a cross-sectional diagnostic trial involving children suspected of having IgE-mediated allergy to egg, cow's milk, sesame, or cashew nuts. The study participants underwent various tests and procedures, including DBPCFC, BAT, SPT, clinical evaluations, and specific IgE testing.

● The results of the study showed that the BAT outperformed other tests in accurately diagnosing egg allergies.

● The BAT exhibited the highest diagnostic performance in children under the age of 2, with an area under the curve (AUC) of 0.867.

● The AUC is a measure of the test's ability to distinguish between allergic and non-allergic individuals.

● When sensitivity and specificity cut-offs of 100% were applied, the diagnostic accuracy of the BAT reached 100%.

● This means that the BAT was able to correctly identify all cases of egg allergy without any false positives or false negatives.

● The use of the BAT significantly reduced the need for oral food challenges (OFC) by 41%.

● By combining sIgE testing with the BAT, the number of BATs performed could be reduced by approximately 30% without compromising diagnostic accuracy.

The researchers highlighted the clinical implications of their findings, emphasizing that the BAT provides a safer and more comfortable diagnostic process for patients. By reducing the reliance on DBPCFC, which can lead to allergic reactions of varying severity, the BAT offers a more reliable and efficient method for diagnosing egg allergies. The findings also suggest that the BAT could be a valuable tool in reducing the number of unnecessary OFCs, which can be time-consuming and invasive.

Overall, the study demonstrates the potential of the BAT as a highly accurate diagnostic test for egg allergy. Further research is needed to validate these findings and explore the application of the BAT in diagnosing other food allergies. The use of the BAT in clinical practice could significantly improve the management and treatment of food allergies, leading to better outcomes for patients.

Reference:

Krawiec M, Radulovic S, Foong RX, et al. Diagnostic utility of allergy tests to predict baked egg and lightly cooked egg allergies compared to double-blind placebo-controlled food challenges. Allergy. 2023 Jul 7. doi: 10.1111/all.15797. Epub ahead of print. PMID: 37417650.

Santos AF, Douiri A, Becares N, et al. Basophil activation test dis- criminates between allergy and tolerance in peanut-sensitized children. J Allergy Clin Immunol. 2014;134(3):645-652. doi:10.1016/j. jaci.2014.04.039.