Allergy & Intolerance Testing
This is a HUGE topic. You might find the Definitions page on the clinic website helpful, plus the whole allergy and intolerance section (look at the drop down menu in the A-Z all the various pages). Please bear in mind that we don't yet know all the likely mechanisms involved in sensitivity, so we can only test for the ones we do - and I try to keep up with the latest advances to help you get answers that are as accurate as possible, but 100% accuracy simply doesn't exist yet.
Please click on the test links given below to see more detail, collection instructions, sample reports etc...
Classical IgE allergy
The medical definition of food allergy is an immediate immune system reaction sparked by the binding of an IgE antibody to a mast cell thereby causing a release of histamine. It is this type that confers a risk of anaphylaxis. Here, you can look at foods or inhalants eg. for hayfever, rhinitis, asthma sufferers etc. Also, don't forget that a high IgE can signify a parasitic infection too, check the gut tests for help if you suspect that.
The most common reaction for inhaled allergens is IgE. I've listed the Biolab IgE Inhalant Panel, which looks for 30 of the most common ones including animal fur, dust mites, pollens and moulds. You can read more about it here. Also, look at Cyrex 11 and 12 (more on these below). For IgE foods, the best is Genova's IgE Food Panel, which tests 19 common foods, plus total IgE.
Even though IgE classical allergy is the one most accepted in mainstream medicine, food intolerance is much more prevalent, certainly in my experience! The overall definition of food intolerance is a delayed reaction to a food which does not involve IgE, the symptoms of which are extremely varied and can be behavioural, emotional or cognitive as well as physical. It is worth noting that a reaction may only be 'delayed' by a matter of minutes, but is usually from 2-4 hours later and can last several days (3 mostly, but more mildly up to 10 is very common). There is a sense that allergy is worse to have than food intolerance and that is understandable because of the risk of anaphylaxis. However, food intolerance sufferers are often sensitive to more foods and have more frequent reactions affecting more body systems so it can be awful to live with in a different way.
Some types of reaction, but not all, involve antibodies such as IgG, IgA and IgM. IgM suggests an early reactivity, IgA signifies a developing problem and IgG, the most common one tested for, usually denotes a chronic problem with a food. There are four sub-classes of IgG: 1-4. However, research suggests that most of us can develop IgA and IgG antibodies to foods and that whether we will react to them or not depends on if those antibodies have activated complement, a part of the immune system known to trigger an inflammatory cascade in the body. Newer tests have been developed that now allow us to measure the antibodies and see if they are bound to complement. This usually results in far fewer positive foods and helps us target the key problem foods rather than getting a whole list of possibles. This is good news!
The Food Inflammation Test (FIT) is, happily, a dried blood spot test so no need for blood samples or centrifuging. It measures all four IgG sub-classes and complement (C3d). 132 foods, additives etc - including all of the gluten cross-reactive foods in Cyrex 4 as well as candida and zonulin to check for leaky gut. We all have some candida in the system. If you find it bound to complement, it has gone through the gut barrier. You can read more, see sample reports and collection instructions here. They do a meal plan with one of their tests but it is quite US-heavy and I didn't rate it that much so I've listed the cheaper one without the meal plan. If you prefer to have it, just ask and I'll confirm the price. They also do a smaller 22 foods test with most of the key problem foods on so I've listed that too for you. You can see the food list for that one here.
Do bear in mind that you have to be eating a food regularly for an antibody to show up on testing. After a couple of weeks, the antibody levels start to drop so you won't find them!
Generally, you do the FIT test, knock out the highest offending foods for minimum 8 weeks (preferably 12), re-test to see if the immune complexes have come down sufficiently and, when they have, you reintroduce one at a time, noting symptoms. You then retest if you wish again (or just enjoy your new-found energy and health!) and make sure that the immune complexes are not rising again. If you still react to something, you need at least a year off it, by which time the inflammation complexes should have reduced sufficiently (the average seems to be 10.5 months according to the lab), then start the reintro and retest process again. In general, anti-inflammatory treatment should be done alongside the removal of the foods to help lower the systemic inflammation in the body; I'll help you with that, don't worry.
In cases where autoimmunity is present or a significant risk, I would also look at doing Cyrex testing as well as FIT. The Cyrex 3 and 10 panels measure a combined total of IgG and IgA antibodies, but without the complement. I talk a lot more about Cyrex tests in the Gluten Tests section of the shop, but, in brief: Cyrex 3 confirms gluten and wheat sensitivity, Cyrex 4 confirms cross-reactive gluten foods (or do the FIT above instead) and some common foods eaten as substitutes and Cyrex 10 is a much larger, very comprehensive food panel but doesn't include the gluten or cross reactive foods, sadly. They have discounted it by a decent amount if you have the three done together as Array 10C. You can see all the Cyrex tests here. I have to say Cyrex 10 is one the best food intolerance antibody tests (minus complement) I have seen in over 25 years in this business although I know it is not cheap! You can see a Cyrex 10 leaflet here and a sample report here - they all look like this one but with the different analytes tested. There is also a useful video here.
Note: equivocal on the Cyrex results is taken as a weaker positive, not borderline. Cyrex tests mostly need centrifuging. Check the Gluten section for Q&A on Cyrex testing for more on this: Gluten Tests section of the shop.
One thing to remember is that, if you suspect your immune antibody production is low ie. your IgA or SIgA has been low at some point or you have immune issues such as chronic infections, frequent colds, autoimmunity, chronic fatigue or multiple sensitivity, it can often be a good idea to do a Total Immunoglobulins test before any antibody test like Cyrex. If you are not producing much, you could get false negative results. I've put a Total Immunoglobulins test on this section for you in case.
If in doubt on what food intolerance test to do, choose the 132 FIT. If you are autoimmune or at risk of it, or suspect a gluten related disorder, also look at doing some Cyrex testing.
Chemicals & Moulds
Finally, for non-foods, you can do Cyrex 11, a fantastic chemical immune reactivity screen and Cyrex 12 to check for pathogens. You can see more about those here.
Other 'Intolerances' eg Lactose, Fructose, Histamine, Sulphites, Oxalates, Nightshades etc
This is where things get even muddier, sorry! These are usually not the same type of delayed sensitivity reaction at all. Lactose intolerance is not, strictly speaking, an intolerance at all but a deficiency of the enzyme lactase which digests the lactose sugar in milk. In lactose intolerance the undigested lactose sugar ferments in the gut giving the typical digestive symptoms of lactose intolerance. Lactose intolerance has nothing to do with cow’s milk allergy or delayed food intolerance, and although it is possible to suffer from both, they are totally separate conditions. Very few outside the medical profession understand the differences so the three terms are used indiscriminately.
The situation differs for each type of 'intolerance' or maldigestion as I think of them. Have a read of this page on the site here. Lactose can be tested with a genetic swab or a breath test. The jury is still out on which is best so do both if you need to. Most severe cases will be picked up by the gene test and can often be negative on a breath test, just to be really helpful! I tend to favour the gene test simply because giving a lactose-sensitive lactulose to do the test with can unnecessarily making them poorly! You can see the lactose breath/malabsorption test here.
Fructose can be done simply using a breath test; there isn't a gene test yet. You can see the fructose malabsorption breath tests here.
Histamine is another type of test entirely. Again, this is far from perfect testing yet but we can at least see what level of histamine you have in your system and if you have enough of the DAO enzyme needed to break it down.
I can do those tests separately (see Histamine only in the Neurotransmitters section) and I've done DAO only here too, but you get the right info if you have them both done as in the Histamine Intolerance combined test.
Don't be thrown by the name 'intolerance' though, this is a misnomer, what we are actually testing for is body levels of histamine and your levels of DAO, see my article for more on this whole subject here: Could It Be Histamine? And the factsheet on Histamine Intolerance in the A-Z. You can test the main histamine enzymes genetically too, so I have added that if you want to see if genetic weaknesses have contributed to your problem. You can see a sample report here. Incidentally, you can measure histamine levels in blood or urine now just as effectively. The test is from Biolab and is done in blood plasma or urine. I will do blood as the DAO has to be done in blood anyway. If you prefer the histamine in urine, let us know. I have also added a Tryptase test for MCAS/MCAD/mastocytosis.
Sulphites can also be tested, please ask if you need that. I am not currently aware of effective ways of testing salicylates, nightshades etc except for food challenge.
Phew: a minefield, huh? Remember to download the free Allergy 101 factsheet for much more on this.
Oxalates - some people have high levels of oxalates in the body which can be linked to kidney stones, pain disorders like vulvodynia, interstitial cystitis and to behavioural conditions in children, to name a few. You get oxalates from food, yeast and you make some inside the body. The issue comes when you are getting too much in total. You can either do the GPL Oat Test (in the Functional Tests section) or a 24 hour urinary Oxalate test with TDL, which I've listed in this section for you. See the collection instructions here for that one. You can read more about oxalate testing here and GPL has a good blog post on it here.
Testing Hints & Tips:
Q: Can I do the Cyrex Tests if I am off the foods?
Generally, you need to be eating the food regularly to get a positive antibody test, although Cyrex do advise a way forward if you wish to re-introduce foods for testing (not that I necessarily agree with that but it's an option..). There is a whole load of testing hints and tips for the Cyrex tests in the Gluten Tests Overview, so do read those fully and it should answer your questions - towards the bottom of that section.
Q: Can I do allergy or intolerance testing for my child?
A: It depends on their age really and the type of testing you are planning.
IgE classical allergy testing can be done reliably from about 9 months onward. This is because babies do not have a fully developed IgE response until about 6-12 months. The same therefore goes for reliable skin prick testing in my view as that is looking for IgE responses too.
The usual issue with blood tests for little ones is getting the blood. For these tests to be processed the lab needs 1 full serum tube (8-10ml) of blood which can be challenging to draw from children as young as 2 or 3 years old. Some phlebotomy clinics are reluctant to take blood draws from children at such a young age.
Cyrex testing is suitable as long as they are eating gluten or the allergens being tested, but the issue is with getting enough blood as per.
Q: Will steroids affect my results?
They could do, yes. If you have been on a short course of steroids (inhalers or tabs), then the labs usually say test after a few days off them: at least five. If you are on long-term steroids, your results could be affected. It doesn't necessarily mean you can't have tests done but you would have to bear in mind your immune system is likely to be suppressed and therefore any results might show lower than they really are. Read the various test information pages for any specific instructions and do talk to your health professional for advice.
Q: Why is the histamine done in plasma and not whole blood?
A: I am aware that eg. Walsh protocol advises whole blood histamine and Biolab used to do it in whole blood but have now swapped to plasma or urine. I asked them why..
"We used to measure whole blood histamine levels but discontinued it in favour of plasma or urine histamine both of which we believe are more sensitive tests for histamine levels (plasma and urine are equally reliable). I know that the Walsh protocol is quite strict on the sample requirements, but in practice we don’t have any problems finding either high or low levels of histamine using the plasma and urine tests."