Food Allergy Test

Food allergy affects 8% of children, and approximately 4% of adults, and causes the emergence of a variety of symptoms ranging from minor symptoms, to allergic symptoms that may threaten life, so it is necessary to clarify the most important information about food allergy examination, which helps In identifying and avoiding allergenic foods (1)

What is food allergy test ?

Food allergy occurs when the immune system overreacts to a harmless food protein, and it may occur to any type of food or to more than one type. (2) As for examining food allergy, there is no single ideal test that confirms or excludes an allergy to a particular food. Rather, there is a set of diagnostic methods that help determine the foods that a person is allergic to and advise to avoid them, and we will explain them in detail in the following paragraphs. (1) What are the types of food allergy tests? How is it performed? Here are the most common types of food allergy tests, how to do them, and an explanation of how to interpret the result:

1. Skin Prick Tests

One of the basic tests on the food allergy checklist is the skin prick test, which results in 20-30 minutes and gives an idea of the types of foods that a person is allergic to and should be avoided.

• How is this examination performed?

A liquid containing a small amount of the allergen is applied to the skin of the patient’s arm or back, and then the skin is pricked with a small, sterile needle to allow the liquid to seep under the skin. A non-allergenic liquid is also applied to another area, and the skin is pricked to compare results.(3)

• How are the results interpreted?

The appearance of blisters that resemble bumps from a mosquito bite indicates an allergy, and the absence of any blisters or a reaction indicates that this does not happen.(3)

2. Blood tests

In this test, the degree of response of the immune system is measured, by determining the amount of allergy-related antibodies known as Immunoglobulin E (Immunoglobulin E) for specific foods being tested, such as: milk, eggs, peanuts, wheat, soybeans, shellfish, cod, And others.(3)(6) Dear reader, it is necessary to inform you that immunoglobulin E is a type of antibody, which is produced by B cells in response to allergens, pathogens, cancer cells, and any other threats to the body. (4) In general, this test is less accurate than a skin prick test, and results are visible within about a week of the test.(3)(1)

• How are the results interpreted?

This examination is performed by collecting a sample of blood from a vein in the patient’s arm using a small needle, and then the blood is placed in a package designated for analysis in the laboratory with different types of food. (5)

• How are the results interpreted?

The result is interpreted based on the IgE value and compared to the reference range, which depends on the person’s age, as follows: (6)

● Newborns: 0 – 4 IU/ml.
● Older children and adults: 0 – 148 IU/mL.
The following table shows immunoglobulin levels and possible explanations: (6)