At Allergenuity Health, we spend the time to collect and carefully consider your medical history, environmental influences, immune system function, and important test-related factors in order to provide you with a thoughtful interpretation of what a specific blood IgE result may mean for you (or your child).
We all wish that a “negative” blood IgE simply meant that you are not allergic, a low blood IgE meant you are only mildly allergic, and a high blood IgE meant you are very allergic. If this was the case, blood IgE would be a great diagnostic test, and tracking blood IgE levels of time would clearly tell us if your allergies were getting worse or better. (And our job would be so much easier!) However, that is unfortunately not the case. Even though this is how blood IgE tests are sometimes used by companies selling allergy treatments and even some providers running these tests, using blood IgE tests this way gives an overly simplistic and possibly incorrect interpretation of what your results mean, and this can lead to misdiagnosis, treatment mismanagement, and a lot of frustration and confusion.
A high amount of IgE in the blood for an allergen only suggests that you may be also highly sensitized for that allergen – meaning that there is a lot of IgE to that allergen also bound to your allergy cells, priming them to react very easily when also in contact with the allergen. However, that is certainly not always the case, such as when a specific type of IgE gets produced in large amounts but does not bind properly to allergy cells, or when there are either not a lot of available IgE binding sites on the allergy cells or just not many IgE receptors in general (as may be the case in a tolerant or calm immune system).
Likewise, a “negative” or low amount of IgE in the blood only suggests that there may not be much IgE on your allergy cells, but does not confirm this to be true. An example of this is when IgE binds to nearby allergy cells after it is produced, bypassing the need to travel through the blood in any substantial numbers. So there may not be much IgE present to a particular allergen in the blood, but it could be present in high amounts on nasal allergy cells causing severe nasal allergy symptoms in the presence of that allergen, for instance.
Additionally, commercial tests for blood IgE may also be lacking the ability to detect the exact type of specific IgE that your body has produced towards an allergen because these tests of course cannot measure everything, so they are set up to measure what they can and what is most common.