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What is IgG?

What is IgG?

IgG is a type of antibody (immune response) which can be formed when you react to foods. A simple blood test is used to measure food-specific IgG antibodies to identify foods to which a person may be sensitive.

This type of testing is now considered mainstream as many choose to use this approach as a starting point for an elimination diet.

Food-specific IgG: Antibodies are major components of the immune system

yorktest lab test tubes

Immunoglobulin (IgG) is a type of antibody. Antibodies are major components of the immune system. There are 4 types of IgG. In normal human blood IgG1 is the most prevalent making up 60-70% of the total IgG, followed by IgG2 (20-30%) and IgG3 (5-8%). IgG4 only consists of 1-4% of the food-specific IgG antibodies present.

The testing

Why do some tests only measure IgG4?

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There are different types of food-specific IgG antibodies that can be measured; IgG1, IgG2, IgG3 and IgG4. yorktest measure all four subtypes of food-specific IgG and we therefore describe our IgG testing as food-specific IgG (1-4) testing. We cover all bases to give you your individual food fingerprint.


Clinical evidence

How accurate is a test for IgG4 only?

Young woman wearing glasses in a laboratory

There is a complex relationship between the four IgG subtypes. Meaningful results can only be determined by testing for all four subtypes together.

IgG1, IgG2 and IgG3 are all capable of causing inflammation which could contribute to symptoms. IgG4 antibodies are only present in low levels and its presence does not relate directly to inflammatory reactions.

Therefore, testing only for IgG4 antibodies in foods severely limits the ability to measure the breadth of reactions which means that your elimination diet may not be as effective.

The substantive YorkTest evidence base for food-specific IgG guided elimination diet supports this approach and recognises the fundamental importance of measuring IgG1-4 (total food-specific IgG) and not just IgG4 alone.

Our range of tests

Which test is right for you?

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Did you know that the average person who has positive food-specific IgG (1-4) triggers reacts to four to five food and drink ingredients?

We have a range of tests that could help you uncover what ingredients work for and against your body. Our team of qualified nutritional therapists can talk through your results and offer advice once you have received your results. If you are unsure what test to take our customer care team is on hand to guide you to the right test. Simply call them on 01904 410 410.