Hi Melissa,

I have mixed thoughts about IgG testing.

On one hand, it's not like the tests are "false positives."  Your body really is making antibodies to foods... interpreting them as foreign invaders (as if they were a virus or bacteria).  I've only had one IgG test... to gliaden (wheat protein) as part of a celiac panel.  Even after several months on a gluten-free diet it was elevated, which made me feel more confident about the need for a gluten-free diet.  I also think that someone with a mast cell disorder is better off reducing his/her exposure to things that set off an immune response.  So... I do think the IgG testing has a useful role to play.

Two downsides... 1) IgG testing is rather expensive, it's typically not paid for by insurance, and in many cases it just tells you what you already knew.  I already knew I had a problem with wheat.  The test just confirmed it.  2) If you eliminate those foods from your diet, your antibody levels will go down.  That's what makes some people say these tests are "false" or "worthless."  Here's the thing... you want to be careful that you don't restrict your diet to the point that you start developing antibodies to new foods!  That can get very dangerous.  The best advice I have is to eat as rich and varied a diet as you can comfortably stand.  Don't eat foods that really bother you, but do keep rotating the foods you can tolerate in order to avoid making new antibodies.  Make sense?

Heather

I am also pondering the place of IgG. I have heard different things about it. I have a friend who has many allergies and intolerances, her experience of it is that it has proved to be quite accurate for her, but she always confirms the IgG results with elimination and challenge.  I had my son tested a while back not by my regular doctor , but I didn't have a high level of trust in the doctor who did it, as she was saying and recommending things that didn't always add up or correlate with what I knew from other credible sources. However, her explanation of the role of this testing is that there are different types of IgG (4 I think) and that the test doesn't isolate which type is reacting. The postivie result could be from the IgG that is the 'normal' type that your body uses to dealing with a food, and so it just tells you what you have eaten, not that you have actually had an adverse reaction to it. Her view is that it gives you a starting point for isoalting foods that may be causing problems, narrowing down the field. Then she lost me when she said you test those things with intradermal testing?? I thought that tested for IgE reactions?  And with dermographism I wasn't sure if it would be valid anyway, and she didn't have a clue about that.  So I have filed his results away as interesting, and we probably should move onto elimination and challenge, but on the basis of her confused explanations and recommendations I wasn't prepared to restrict the diet of a teenager, without a clear reason (he tested positive for gluten, dairy and eggs - that would be a huge upheaval for him to exclude all of these completely).  I have tried to reduce the amount of those things, substitute where it is easy to do, and vary his diet more.  If anyone has further insight into IgG I would love to hear more about it.

Thanks Heather, I did join it recently probably when looking up something from the old forum I was reading.  I will take a look at this. I am still in the dark as to whether to take his IgG results seriously or not, I guess only elimination will tell me, but I am reluctant to go that route if it's not warranted.