001. three NDs:
001.a. Ontario's ND Watson (CCNM 2007) tells us in "Food Sensitivity Testing" [2015 archived]:
"IgG Food Sensitivity Testing:A finger-prick blood test is analyzed by a specialized laboratory to assess for IgG (immunoglobulin G – one of two antibodies produced during an allergic response). IgG antibodies are produced for several hours or days after exposure to an allergen (which is one of the reasons why some symptoms of sensitivity/intolerance don’t occur immediately after eating a food). Advantages: Gives a clear outline of food intolerances and the severity of the intolerance. Tests for a wide variety of commonly consumed foods. Only a small amount of blood is required for the test and it can be done in office or at home. Antihistamine use is permitted during the test. You can see the complete list of foods tested for here. There is also a vegetarian panel available here.Disadvantages: Can be expensive. Food must be consumed within 3 weeks prior to the test for an accurate reading [...] in my Toronto clinic I use only the elimination diet and IgG food allergy blood test to assess for food allergies or sensitivities. Clinically I have found these two tests to be the only measures of food sensitivity to accurately identify sensitivities and have a corresponding improvement in patient symptoms[...] there is also abundant evidence that IgG (immunoglobulin G) is an important marker for allergy testing. IgG and IgG complexes are involved in 80% of all food allergy or sensitivity reactions. IgG is involved in delayed immune responses which are more common in food intolerance."
so, safe to say, the ND claims this works diagnostically speaking.
001.b. Washington State Bastyr NDs Franks, Orth, and Torrance (see bio.s here) tell us in "Food Sensitivity Testing" [2015 archived]:
"what is IgE and IgG testing? When the immune system recognizes a foreign substance, it produces antibodies to fight off the allergens. IgG and IgE are two different types of antibodies produced in allergic reactions to food. IgE reactions are immediate and usually more severe, such as hives, swelling of the tongue and sudden diarrhea. IgG reactions are more common and more subtle and can result in many other delayed symptoms such as chronic pain, sinusitis, constipation, diarrhea, bloating, gas, fatigue and abdominal pain."
001.c. Ontario's ND Dickson in "Allergy Treatment" tells us:
"defining food allergens: the immune system reacts by releasing cells called antibodies. Foods that cause antibodies to be released are called allergens. Two types of antibodies commonly produced in response to foods are IgG (immunoglobulin G) and IgE (immunoglobulin E) [...] IgG reactions take hours or days to develop. This makes it almost impossible to discover which foods are causing the problem without testing. In an IgG reaction the IgG antibodies attach themselves to the allergen and create an antibody-allergen complex. These complexes are normally removed by special cells called macrophages [...] the allergen-antibody complexes accumulate and are deposited in body tissues. Once in tissue, these complexes release inflammation causing chemicals that may contribute to disease. Conditions associated with IgG food reactions: weight gain [...] digestive disorders [...] mood/attention deficit disorders [...] asthma or other respiratory problems [...] eczema [...] hypertension [...] testing: Dr. Dickson identifies allergens and/or sensitivities are using IgG blood markers through outside lab testing. However, applied kinesiology is also used, a safe technique that is able to detect allergies/sensitivities on the spot [...] treatment: allergy treatments are non-invasive and painless. After only one treatment, the body will no longer see the allergen or intolerance as a threat when exposed to it, therefore desists in producing any adverse reaction."
really. She does that.
002.a. Laurie Laforest at foodconnections.org writes in "Myths Used to Justify Food Intolerance Blood Tests (IgG tests)":
"no blood test can detect food intolerance, not even the IgG/IgG4 ELISA tests that check for ‘hidden food intolerances’ to over a hundred common foods [...] in fact, allergy and immunology associations around the world have issued position statements warning against IgG blood tests, which they see as leading to potentially dangerous dietary restrictions, overlooked conditions (including true allergies), and unnecessary costs. Immunologists have found no evidence that IgG antibodies cause delayed food allergies or intolerances [...there are at least] six myths that are used to support food intolerance blood tests: high levels of IgG antibodies mean that you have a hidden or delayed reaction to food, food-specific IgG antibody levels correlate with chronic symptoms, IgG antibodies degranulate basophils, IgG antibodies cause inflammation, IgG blood tests detect Type III hypersensitivities, diets based on IgG levels have been shown to successfully treat symptoms."
002.b. at sciencebasedmedicine.org, we're told in "IgG Food Intolerance Tests: What Does the Science Say?":
"at present, there are no reliable and validated clinical tests for the diagnosis of food intolerance. While intolerances are non-immune by definition, IgG testing is actively promoted for diagnosis, and to guide management. These tests lack both a sound scientific rationale and evidence of effectiveness. The lack of correlation between results and actual symptoms, and the risks resulting from unnecessary food avoidance, escalate the potential for harm from this test. Further, there is no published clinical evidence to support the use of IgG tests to determine the need for vitamins or supplements. In light of the lack of clinical relevance, and the potential for harm resulting from their use, allergy and immunology organizations worldwide advise against the use of IgG testing for food intolerance."
just more naturopathic pseudodiagnostic nonsense, that costs people $$$$$ and causes a lot of needless grief. And the fakery marches on...