The gold standard for food allergy testing is the oral food challenge, which is a medically supervised, gradual process of introducing a food allergen to a patient in order to diagnose or rule out a food allergy.
The doctor may also use an Immunoglobulin (IgE) blood test, which measures the presence of allergen-specific IgE antibodies in your blood after being exposed to a food allergen. The immune system makes antibodies to fight the food allergens that it mistakes as invaders. The (IgE) blood test can test for common food allergies, as well as different mixes of allergens.
How is an IgE Blood Test Performed?
An IgE blood test is done by inserting a needle into a vein in the arm or back of the hand, collecting a blood sample, and pulling it into a vial. The blood sample is sent to a laboratory to assess the response to different types of food allergens. Results can take a few weeks to become available. The results are given in numbers that range from 0.10 kU/L to 100 kU/L. Keep in mind that the results do not determine the severity of a reaction to a food allergen (such as anaphylaxis), only the level of antibodies produced after being exposed to the allergen.
How To Interpret Results
The results of a food allergy test can be confusing for someone with no medical training. As food allergy tests become widely available, more and more people are having to interpret results for themselves.
Here’s what the scoring system is like and what it means:
- Values under 0.35 mean unlikely sensitization to the allergen.
- Values between 0.35-0.69 mean doubtful significance.
- Values between 0.70-3.49 mean there is a possibility.
- Values between 3.50-17.49 mean a greater possibility.
- Values between 17.50-49.99 mean very likely.
- Values between 50.00-100.00 mean very high likelihood.
- Values over 100.00 mean extremely likely.
The higher the number, the more likely it is that the food allergen is causing the allergy symptoms.
Why Seek An Allergist?
Attempting to self-diagnose food allergies and interpreting results can be challenging. With food allergy tests, false positives and false negatives can occur. For this reason, you should always seek out a board-certified allergist to diagnose and treat your symptoms. Moreover, laboratories use various blood tests with different scoring systems. An allergist, however, is an expert and will be aware of the differences and know how to accurately interpret the results and explain to you what the results mean.
Food allergy testing is an important part of making a diagnosis. However, an allergist has many tools that increase the accuracy of a diagnosis, such as taking into account your medical history, using the elimination diet, and using other methods of food allergy testing (such as skin testing).
Food Allergy Testing in Downers Grove, Naperville, Elmhurst, and Plainfield, IL
At Oak Brook Allergists, our board-certified allergists do not leave you to figure out your food allergies and interpret the results of various tests yourself. We are with you every step of the way. Our team is experienced in diagnosing and treating food allergies in adult and pediatric patients.
To schedule an appointment with an allergist, call us today at (630) 574-0460 or use our online request form. We look forward to helping you successfully manage your food allergies.