The Basophil Activation Test (BAT) can be used for the in vitro detection of immediate type allergic reactions and hypersensitivities to suspected allergens.
BAT is able to detect both IgE and non-IgE mediated allergies, making it suitable for the diagnosis of a range of different types of allergy, including food and drug allergies.
Choose from the CAST ELISA or the Flow CAST whole blood flow cytometry method, manufactured by BÜHLMANN Laboratories.
With over 150 standardised allergens including food, food additives, drugs, insect venoms and inhalants.
The physical symptoms of allergy can be similar to that of a sensitivity or intolerance. Roughly 20% of the population experience symptoms that make them believe they have a food allergy, but it’s estimated that only 1-10% of adults and children actually have a food allergy. The incidence of food allergies are becoming increasingly more prevalent; it’s estimated that, in the UK, 1 in 40 infants are developing a peanut allergy, and 1 in 20 infants are developing an egg allergy. With almost a third of allergy sufferers having to change their lifestyle, it’s vital to determine who is truly allergic from those who are not; BAT can be a helpful tool to do this.
About 10% of the general population claim to have a penicillin allergy, however fewer than 10% of people who think they are allergic to penicillin are truly allergic. Those with a label of penicillin allergy are more likely to be treated with broad-spectrum antibiotics, and use of broad-spectrum antibiotics is associated with an increased rate of clinical complications, such as antibiotic resistance. An unsubstantiated label of penicillin allergy may lead to the inappropriate use of broad spectrum, non-penicillin antibiotics leading to antibiotic resistance and in some cases sub-optimal therapy.
The general pathway for suspected allergy diagnosis recommends the following:
- Firstly, a detailed clinical history of the patient will be taken
- Based on the results of the clinical history, a healthcare professional will offer a skin prick test (SPT) and/or a blood test for specific IgE (sIgE). The results of these tests will then be interpreted along with the results of the clinical history
- If the results from the SPT and sIgE tests are unable to confirm or exclude allergy conclusively, patients may be referred to specialist or secondary care settings for further investigation (e.g. challenge test)
Challenge tests can be unpleasant and stressful for patients and their families, as well as posing a danger to the patient. BAT can be used as a safer alternative to a challenge test if SPT and/or sIgE testing cannot offer a conclusive result- if the patient has a positive BAT result, allergy can be confirmed with a high degree of certainty; if the patient’s BAT result is negative, patients may be offered a challenge test to definitively confirm or exclude allergy.
Offering BAT before a challenge test will significantly reduce the number of patients having to undertake these tests; a peanut study undertaken by Santos et al. in 2014 has shown a 67% reduction in the need for oral food challenges. The true value of BAT lies in its high specificity, reaching 100% in some studies. This means that a positive BAT result confirms allergy with a high degree of certainty, resulting in fewer of the more dangerous positive challenge tests being performed.
Road map for the clinical application of the basophil activation test in food allergy
Santos, A.F. and Shreffler, W.G. Clin. & Exp. Allergy Volume 47, Issue 9, September 2017, Pages 1115–1124
Basophil activation test discriminates between allergy and tolerance in peanut-sensitized children
Santos at al. Journal of Allergy and Clinical Immunology;Volume 134, Issue 3, September 2014, Pages 645–652
Diagnosis of Immediate-Type ß-Lactam Allergy In Vitro by Flow-Cytometric Basophil Activation Test and Sulfi doleukotriene Production: A Multicenter Study
De Weck at al. J Investig Allergol Clin Immunol;Volume 19, Issue 2, 2009, Pages 91-109