In a paper in the journal Lab on a Chip, Tang and her colleagues outline the basis for this future allergy test, which isolates a food allergy marker from the blood using a magnetic field.
Sindy Tang, Ph.D., is an associate professor of mechanical engineering at Stanford University in California.
The available allergy diagnosis exposes allergic patients to the risk of anaphylaxis, an allergic reaction that causes inflammation so severe that breathing becomes restricted and blood pressure drops. Because of that, a clinical team must be at the ready with treatments like oxygen, epinephrine, or albuterol.
For these reasons Tang and her colleagues are developing a food allergy test that’s not only safer but also more reliable and accurate than today’s tests.
In their study, the Stanford researchers focused on a type of white blood cell known as basophils, which release histamine when triggered by allergens. By using magnetic nanoparticles that bind to some blood cells but not basophils, they were able to separate basophils from the blood with a magnetic field in just 10 minutes.
Once isolated, the basophils are exposed to potential allergens. If they react, that’s a sign of an allergy.
Basophils have been isolated in labs before, but not nearly this quickly and efficiently, Tang says.
“For true basophil activation, you need the blood to be fresh, which is challenging when you have to send it to a lab, Tang says. Being able to do this kind of test within a clinic or an in-house lab would be a big step forward.”
While this represents a breakthrough in basophil activation testing, more research is needed to fully develop the system for clinical use. It must be standardized, automated, and miniaturized, the researchers say.
That said, the results give hope to those with food allergies that tomorrow’s gold-standard test will require only a blood sample without an emergency team standing by.
Parvathy Sukumaran 
