Why Do We Test IgG4 Over Total IgG Or IgG1?
The main difference between IgG1 and IgG4 is how they respond to food antigens. IgG1 antibodies are like ‘first responders’ and are produced in response to new food antigens. Whereas IgG4 antibodies are produced when the body is continually exposed to an antigen.
Therefore, testing for IgG4 over IgG1 or total IgG is an advantage, as it leads to a reduced number of false-positives and allows for much more targeted, relevant results. It reduces the incidence of patients avoiding too many foods unnecessarily, therefore improving patient compliance and outcome.
You can learn the more in-depth science behind the production of IgG1 and IgG4 antibodies here.
IgG1 and IgG4
Testing for IgG antibodies is required to identify immune-mediated intolerances. Within the IgG class, there are four IgG subclasses. There are a range of IgG tests, available to health professionals all over the world, some testing all subclasses and others testing one subclass but there is still debate about which is the most effective.
The subclasses most commonly tested are IgG1 and IgG4, as these are produced in response to food antigens and therefore can be used to identify intolerances. IgG2 and IgG3 are not generally produced in response to food antigens.