What is the minimum specimen requirement for this test?*
- Serum - 2mL
- Bloodspot - Four spots of blood the size of a standard hole punch completely filled and completely soaked through to the other side of the collection card.
My bloodspot test went outside of the circles on the collection card, is this okay?
Yes. As long as you have filled the circles and the blood has soaked through to both sides, it does not matter if the specimen goes outside of the lines.
How long do I have once the specimen is collected to get it to the laboratory? (Please see proper specimen storage under the "Shipping" section)**
- Serum - within 21 days of collection
- Bloodspot - within 8 weeks of collection
What is the difference between IgG and IgE testing?
IgE allergies are the most commonly known allergies. These are what we think of as "classic" allergies. Common examples include bee sting resulting in hives, eating peanuts resulting in swelling and the more severe reaction, anaphylactic shock. IgE reactions are immediate and typically easily recognized.
IgG sensitivities are much different and less well-known. These are what we think of as "delayed" or "hidden" allergies. IgG sensitivities are more difficult to detect due to the fact that reactions probably will not take place immediately following the consumption of the reactive food. Reaction can also vary. For example, some people with IgG sensitivities might experience muscle and joint aches; others might notice behavioral differences, while still others might experience intestinal symptoms. It should be noted that IgE and IgG reactions are different; that is to say, you can have an IgE allergy to a food and not an IgG sensitivity and vice-versa.
I have avoided certain foods for a while. Should I reintroduce them into my diet before I take the food allergy test?
In order for those foods to show an IgG reaction they need to be regularly consumed prior to the test. IgE responses are permanent, so the food does not need to be consumed prior to testing. Foods that you are sensitive to would react even if you do not eat them at all.
I reacted to certain foods but the test does not measure other related foods. Should I eat foods related to the ones to which I am sensitive? Ex. Green peppers and red peppers
For all foods not tested, the rule to follow is frequent rotation to reduce the possibility of allergic reactions. This means that the food may be eaten in a meal or two, but then you need to allow several days before eating those foods again. You may also refer to the food families in your IgG Food Reaction Patient Guide. Foods that are grouped together may be eliminated together to avoid reactions.
I reacted to milk on the IgG4 90 or IgG 30 bloodspot test; does that mean I am lactose intolerant?
The reaction is an IgG (antibody) response to whole milk and to fractions of milk such as casein. Lactose intolerance is completely different. It means you do not have adequate amounts of lactase, the enzyme needed to break down lactose, a natural sugar in milk. We do not test for lactose.
What is the difference between a reaction to casein and a reaction to milk on the IgG 90 serum test?
Milk protein consists of casein and whey. The IgG4 reaction to milk looks at the total protein. The IgG4 reaction to casein looks specifically at casein. Subtracting the casein reaction from the milk reaction will give an estimate of the whey reaction.
What is Celiac Disease and does Metametrix test for it?
Celiac disease is an autoimmune disorder of the small intestine when the body reacts to gluten. This reaction can lead to damage of the mucosa, resulting in malabsorption, which means that your body is not absorbing some nutrients properly. Clinical presentation is varied given the possibility of widespread nutritional deficiencies, but those most commonly seen are, bloating, anemia, fatigue, weight loss, constipation and diarrhea. Metametrix has a full celiac panel. It includes: Total Immunoglobulin A (IgA), IgA Transglutaminase antibody, and Anti-gliadin IgA II. We also offer an IgA-antigliadin assessment of stool in our GI Effects Stool Profiles.
Is an IgG wheat reaction the same as gluten intolerance or Celiac disease?
The two situations are closely related. Gluten is the major antigenic protein in wheat. In the IgG test, extracts used are the protein-containing fractions to eliciting the antibody response. If a patient has a high wheat IgG antibody reaction, it is often due to too much wheat in the diet. Similarly, if a person has gluten sensitivity, he or she will have an elevated reaction to wheat. If there are many reactions to other foods, intestinal permeability is most likely the underlying problem.
At what age is IgG food allergy testing accurate?
The immune system is not fully developed until about 9 months of age. Beyond that age, the IgG production from food antigen presentation is active. The test will show the presence of specific food antigen presentation due to increased permeability of the small intestine.
The kit instructions state, "the use of immunosuppressive drugs, like cortisone, can give false negative test results. Discontinue the use of such drugs for 60 days before testing to allow antibody reaction to be seen." What all does this include?
If used long enough, any steroidal medication will affect test results; this includes topical medications and inhalers. We understand that many people with asthma rely on their inhalers daily and cannot discontinue use for the required period of time. You and your clinician should discuss the possibility that positive results may appear weaker under these conditions. Ex. for IgG testing, a +5 severe reaction may show as a +4 instead.
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