Best Way To Test For Food Allergy
This is a common question we are asked, what is the best way to test for food allergies? The best answer is, it depends. In some cases the blood test is the only test you need to do, other times it is the skin test, and many times it is both. The problem is neither test is perfect or close to 100% accurate. When dealing with such an important condition as food allergies, we need as accurate a test and diagnosis as possible.
An incorrect diagnosis has many implications. A false + test often leads to a false + diagnosis so food avoids unnecessary and the family needlessly worry. We have seen complications of poor nutrition and poor weight gain when too many foods avoid. A false-negative test is more concerning as the family food does not avoid that may trigger a serious allergic reaction. This is very dangerous as the family is not aware and is often not prescribe an epi-pen.
Skin Allergy Test Results
The allergy skin test is helpful to diagnose food allergies for years and years. A small drop of a dilute form of the food is placed on the skin, it scratch and the results are ready in 15 minutes. A reaction that looks like a mosquito bite is measured in mm as to the bump as the wheal and the surrounding redness called the flare. Results larger than the + skin test control are considered positive. The test is quick, the results available within minutes, and the wheel and flare response are a nice visual for the parents to see. A negative skin test response is highly accurate and often indicates the child is not allergic to the tested food. Unfortunately, in many cases, there are false-positive skin tests s and the clinical signs can be tricky.
Blood Test
Blood tests on the other hand, while easy to order and obtain are often very difficult to correctly interpret. A strong positive blood test result tends to be very reliable that a food allergy exists. However, in many cases, the scores are in the low positive range. The weak + blood scores are a clinical challenge. In one child with a blood score of 2 for peanut, he may eat it fine while another child with the same score may end up in the hospital with a severe reaction. To make matters more confusing, a blood score may give a false negative result 10-20% of the time. As stated above, a false negative result is a potentially very dangerous situation.
For both the blood and skin tests, the results only predict the likelihood of having a reaction, neither test will predict the severity of the reaction. The child with a peanut score of 5, may react more severely and require the use of an epic pen while a child whose score is >100, may just need Benadryl to treat his reaction.
At Mediyaar, in our Allergy Checkup Packages, we find a careful approach of obtaining an accurate clinical history, and the proper utilization of blood and skin test results helps us to obtain the most accurate diagnosis which is essential to successful food allergy management.
