Your Guide to Testing for Allergies and Intolerances


Foods Matter, November 2007Michelle Berriedale-Johnson attempts to chart a course through the complexities of allergy testing – Like so much in the field of allergy, testing is bedevilled by terminology. Procedures as varied as a RAST blood test for peanut allergy carried out in a hospital allergy clinic, a postal IgG food intolerance blood prick test or a health food store Vega food-intolerance test are all referred to as ‘allergy tests’ – thus invoking the fury of mainstream allergists who point out, quite correctly, that most of these tests are completely useless for diagnosing classic, Type 1 immediate hypersensitivity.

However, the majority of the non-hospital based tests are not intended to diagnose classical, Type 1 allergy; they are attempting, with more or less validity, to address the problem of illnesses which appear to be triggered, or at least made worse, by the ingestion of certain foods or the contact with (or inhalation of) certain substances ranging from peppers to pesticides.

Test validation

The mainstream medical profession object to most of these tests on the grounds that that have not undergone sufficiently thorough clinical evaluation and have not been subjected to the gold standard of medical research, the double blind placebo controlled trial. The problem is that the very individual nature of allergy/sensitivity, and therefore testing for it, makes it almost impossible to use conventional evaluation methods which require a level of uniformity amongst those tested to enable comparison.

The immune system

An ‘allergic reaction’ is commonly assumed to involve the immune system, yet many symptoms that may suggest that the patient is having an allergic reaction to a food, chemical, mould, pollen etc may not involve the immune system at all.

In medical speak, however, the term allergy indicates an immune system reaction. The immune system is designed to protect the body against harmful invading microorganisms which include proteins, polysaccharides, bacteria and viruses. It both recognises and remembers these substances, which are known as antigens.

However, it appears that sometimes the immune system gets it wrong and identifies a perfectly harmless substance – a peanut for example – as being harmful. Having once identified it as being harmful, that is how it remembers it so that any subsequent contact with that substance (now seen as an antigen) will immediately trigger a defensive reaction (allergic symptoms) even though the substance itself is not going to do the immune system or its owner any harm. Why the immune system should do this remains a matter of speculation.

The defensive reaction – Lymphocytes

Lymphocytes are a type of white blood cell which can recognise an antigen. When they do so they either produce large quantities of antibodies (see below), instruct the immune system how to react, or kill off cells which have been affected by the antigen.


Antibodies are proteins created by the immune system (via the lymphocytes) which circulate in the blood and are designed to neutralise the antigen. It is the antibodies that trigger the release of the chemicals which produce the allergic reaction – swelling of the face, throat and respiratory channels, itching etc. Confusingly, these reactions can occur within seconds (as in the case of a Type 1 reaction) or not for up to 72 hours.

Antibodies fall into five main groups – IgA, IgD, IgE, IgG and IgM. Although similar in structure a tiny section of some antibodies (IgE antibodies in particular) is ‘customised’ to the particular antigen it has been created to neutralise. The customised part is called the epitope and this ‘customisation’ allows the antibody to ‘bind’ or stick to that specific antigen and that antigen only.

The majority of allergy tests measure the number of antibodies (of various kinds) in the blood of the patient. If each antibody is (via its epitope) specific to the antigen it was created to neutralise, matching the antibody in the patient’s blood to an antigen should, in theory, lead the tester to the antigen (food, chemical, mould etc) causing the problem.

IgE antibodies – Type 1 Anaphylactic or Immediate Hypersensitivity

In the case of IgE antibodies this system does work fairly efficiently. When IgE antibodies bind to their antigen (or allergen) they trigger an immediate release of histamine which causes inflammation and tissue damage which, in turn, can cause dramatic respiratory, gastric or skin reactions including anaphylactic shock. Identifying the substance to which the patient’s specific IgE antibodies binds de facto identifies the antigen.

Sensitivity versus reactivity

The presence of antibodies, however, does not guarantee an allergic reaction. There are occasions when a patient carries a very high number of antibodies to a specific substance (eg – is sensitised to it) yet does not react to it.

For example, someone who works with cats might have a high number of antibodies to cat dander because they are in constant contact with them, yet not react to them. Dr Hugh Sampson investigated this subject in some detail in FM June 06 or see the FM website at

This means that in cases where avoidance of the suspected allergen may cause serious lifestyle disruption, the test finding needs to be validated by a controlled food or substance trial.

Elimination and challenge

Any of the tests mentioned so far will, effectively, need to be validated by elimination and challenge – avoiding the suspect food or substance for a period (usually three to six weeks) and monitoring whether the symptoms improve, and then ‘challenging’ the patient by having them eat the food or come into contact with the substance once again and seeing whether the symptoms reappear.

Obviously, when dealing with Type 1 reactions, the ‘challenge’ needs to be carried out under controlled medical conditions so if the patient suffers a serious reaction professional help is at hand.

Some allergists would regard elimination and challenge as the only really reliable allergy test and, having taken a detailed patient history, would go straight for it. There is certainly no doubt that it is the most reliable and can be tailored most precisely to the individual’s needs.

However problems arise when more than one allergen is involved (so eliminating only one may not achieve any significant improvement in symptoms) and where the reaction is delayed, so that it is difficult to attribute a specific reaction to a specific allergen.

It is particularly difficult when dealing with environmental allergens where it may be almost impossible even to identify substances that should be avoided.

Few-foods Diets

If there are multiple symptoms and a number of foods appear to be involved some practitioners will advise a few-foods diet. This reduces food intake to the most basic and simplest foods (lamb, pear and rice are normally thought to be the least allergenic foods). If symptoms improve, then ‘new’ foods are added one by one, and symptoms monitored carefully thus, over the course of time, identifying the culprit foods.

However, this is a really hard regime to follow and requires great discipline and patience on the part of the patient and the doctor. There is also the risk of nutritional deprivation if the diet remains too limited for too long. For a short article on this see Dr Morrow Brown at; for a comprehensive clinical protocol see Dietary Management of Foods Allergies and Intolerances by Dr Janice Joneja published by JA Hall Publications.

Nonetheless, if you can stick with it, an elimination and challenge diet will identify problems caused not only by foods which trigger a Type 1 response but foods which trigger a whole range of other reactions which may be set off by other antibodies or in which antibodies may not be involved at all.

Compliance – or lack of it…

It is when faced with the prospect of a lengthy and restrictive elimination diet or avoidance regime that the average sufferer looks for a test which will identify the problem food (or mould, or pollen, or chemical) without them having to spend months struggling with a severely restricted diet or lifestyle.

Although there are a number of tests which claim to do this on the market, many of which have proved hugely helpful to a large number of grateful patients, none of them have, as yet, been validated to the satisfaction of most conventional allergy specialists. These range from antibody (IgG) and leukocyte blood tests, through energy based assessments to practitioner mediated tests such as kinesiology.

RAST tests

The RAST or radioallergosorbent allergy test – uses IgE antibodies in the patient’s blood to identify Type 1 allergies. RAST tests are available on the NHS and at some private allergy clinics. They are reasonably accurate although they do throw up a significant number of both false positives and false negatives.

Skin prick tests

The alternative diagnostic test used by most mainstream allergists, skin prick testing uses a tiny drop of the suspect allergen (food, pollen, mould, dander, chemical etc) placed on the skin where a small scratch has been made to allow the allergen to penetrate. The degree of allergenicity is assessed by measuring the size of the wheal which appears at the point of contact. When no reaction is achieved with a skin prick, but an allergy is still suspected, the allergen can also be injected under the skin. Skinprick testing is relatively simple to perform and, although most allergists will only use laboratory produced concentrates of allergens, it is possible to manufacture very specific solutions to test for uncommon allergens or allergic triggers. (See Dr Harry Morrow-Brown’s website for more discussion of such tests – Tests are available on the NHS and from private clinics.

Patch tests

These are used mainly to determine whether a skin condition such as dermatitis could have an allergic component. The allergen is placed on a pad which is taped on to the skin for 24-72 hours; the reaction is then assessed. Patch tests are available on the NHS or from a dermatologist.


The ALCAT test which has been around for some 20 years, assesses changes in the size of the patient’s lymphocytes (white blood cells) when they are brought into contact, in laboratory conditions, with individual foods, chemicals etc, thus, it claims identifying the substance which is causing the reaction. The programme suggests nutritionally balanced dietary restrictions (excluding the problem food) which seem to have the added benefit of weight loss for some patients. The ALCAT test does not find favour in many medical circles but is widely used in both US and the UK. Costs range from £50 for testing 10 moulds to £199 for 100 foods. 01638 665 350 NPTech Services Ltd 96-98 Wellington Street Newmarket CB8 8S

IgG antibody testing

The most widely used – and argued over – of these are IgG blood tests, which use an enzyme- linked immunosorbent assay or ELISA system. The question at issue is whether the immune system creates, or ‘customises’, specific IgG antibodies to substances that it finds problematic in the same way that it creates IgE ones – or whether IgG antibodies have no specific relationship to any one food or substance and therefore their presence is no indication of a problem with that food or substance.

However, recent research carried out (and described on the following pages) by Dr Anton Emmanuel and his colleagues suggests that there may indeed be a specific link between the presence of IgG antibodies and bowel conditions such as Crohn’s disease and irritable bowel syndrome and that these antibodies may be linked to specific foods. Based on the assumption that this relationship does exist, IgG testing is on offer via a home skin prick test kit – you can order it on line, on the phone or buy it from a chemist. The two companies that follow arethe leading UK suppliers [but the testing is available in the US and Canada as well].

Cambridge Nutritional Sciences – CNS offer a range of ELISA based IgG food intolerance tests ranging from a £20 Food Detective kit which you can use at home (like a pregnancy test) and which will tell you whether or not you are food intolerant, through a 40 foods (£99), 60 foods (£149), 120 foods (£199) to a 200 foods test (£275). They also offer a vegetarian food test (£149) and a herbs and spices test (£99). Apart from food intolerance CNS also offers tests for anaemia, candida, coeliac disease, helicobacter, intestinal parasites, osteoporosis, rheumatoid arthritis and thyroid. 01353 863279 Eden Research Park, Littleport CB6 1SE

Yorktest offers an ELISA based Intolerance Indicator for £17.50 which will tell you whether or not you are intolerant and then a 113 foods test for £242.50 (to on-line buyers). They also offer a homocysteine test (possible indicator of heart disease or stroke), a house dust mite detection kit and an IgE testing kit, although this requires blood sample drawn by a health professional. 0800 074 6185 York Science Park, York, YO10 5DQ

Both of these companies offer a relatively cheap test which will indicate whether or not you are likely to be sensitive as well as more comprehensive and wide ranging tests. Test results suggest foods (or substances) that should be completely avoided, those that should be treated with care and those that are problem free. The test results usually come with comprehensive nutritional advice.


When an immune system reacts to an allergen to which it is sensitised, it releases histamine plus another group of chemicals known as leukotrienes. Another test blood known as the Food Allergen Cellular Test (FACT) uses the leukotrienes to assess which an antigen has caused the reaction. Non-allergy based problems Although an inappropriate immune reaction to a food or a substance provides a perfectly acceptable explanation for many apparently ‘allergic’ symptoms it is not inclusive.

Setting aside specific and recognised medical conditions such as coeliac disease or diabetes, other health conditions can result in symptoms that can mirror allergic reactions.

IWDL Genova offers a 170 FACT foods test (£245), a dairy and grains test (£105), an additives test (£95), and antibiotics and analgesics test (£95), and a Comprehensive Food Allergy profile (IgE and FACT) for £300, as well as tests for individual allergens at £30 each. It also offers a wide range of other tests not related to allergy. 020 8336 7750 356 West Barnes Lane KT3 6NB

Leaky gut

A serious gastrointestinal upset, long-term poor nutrition, excessive intakes of junk foods, alcohol, antibiotics or other drugs or a major period of stress could all lead to a ‘leaky gut wall’. This would allow partially digested proteins to escape through the gut wall into the blood stream and circulate around the body causing almost any symptom from chronic fatigue to joint pains, constipation or hyperactivity.

In this situation, specific food proteins or parts of proteins may trigger specific symptoms, so removing that food from the diet may reduce the symptoms, even though the problem lies with the leaky gut wall and the patient’s general ill health rather than the food itself.

Temporarily removing that food from the diet will reduce the stress on the system and, if combined with other improvements to diet, nutritional status and lifestyle, will allow the gut wall to heal and the patient’s general health to improve to the point where they are able to tolerate a normal range of foods.

Patients in this situation may well visit their GP and, because their symptoms are non-specific and no organic problems can be found, get little help. In which case they may seek a test elsewhere which can identify their problem.

Some will opt for one or more complementary therapies – which will probably have their own testing protocols – others may seek some sort of test which will identify the food which they think is at the root of their ill health.


One complementary therapy that is widely used for diagnosing food sensitivity is kinesiology, which uses muscle-strength testing to assess which foods or substances may be causing problems. Although the system has no credibility with conventional doctors, when used by a skilled practitioner kinesiology would appear to be able to diagnose intolerances and other health problems very accurately.

However, its success does depend entirely on the skill of the practitioner. For more information contact Kinesiology Federation Box 28908, Dalkeith EH22 2YQ 0845 260 1094

Coeliac disease

In coeliac disease the gluten commonly found in foods attacks the lining of the small intestine both preventing the absorption of nutrients and causing a wide range disparate symptoms which can often be mistaken for allergic symptoms. Coeliac disease is thought to be seriously under diagnosed.

If you suspect it might be relevant to your ill health, you can put yourself on a glutenelimination diet or you can get tested. A number of laboratories offer a coeliac test – or you can get a home-testing kit developed in Australia. If the result is positive you should return to your GP for full diagnosis as registered coeliacs can get gluten-free foods on prescription.

Biocard Coeliac Tests – Finger prick test you can do at home – works like a pregnancy test – £19.95. 0845 430 50 80 PO Box 8014 Reading RG6 9DB

Bio-electromagnetic medicine

Another form of testing which is readily available on the high street (often in health food stores) and by mail order – and which is roundly condemned by most mainstream practitioners – is bioenergetic testing, most commonly known as a Vega test.Bioenergetic or bioelectrical medicine involves the interactions between electromagnetic fields (the environment) and the electrical properties of biological tissues and cells (our bodies) – but it is closely linked to the ancient theories of energy which underpin Chinese medicine.

Energy flow

Both believe that in a healthy body energy (whether seen as ‘chi’ or electromagnetic energy) flows freely and is in harmony with the other energies (or electro magnetic fields) within and amongst which it exists.

However, this free flow of energy can be disrupted by malfunctions within the body itself or by the intervention of outside forces. These forces can be recognised either in their physical/ chemical forms (viruses, bacteria, food proteins, toxins etc) or by their electromagnetic properties. When they come into contact with a healthy body they will disrupt its function. This will both precipitate various physical symptoms – all the symptoms which might cause someone to seek an ‘allergy’ test – but will also cause severe disruption to the energy flow and electromagnetic fields within the body.

So, if you can monitor the electromagnetic activity of the body when brought into contact with foods or substances which disrupt that activity, you can identify the problem substances.

Bioenergetic tests

Most of the early work on bioelectromagnetic medicine was done in the 1950s by a German, Dr Reinhold Voll and forms the basis for a relatively simple machine, called the Vega machine. Subsequently, much more complex computerised testing systems have been developed which also assess the health of the organs and other bodily functions (based on their electromagnetic resonances) and offer a myriad of herbal, nutritional and homeopathic remedies.

The Healthcheck Clinic – Jackie Young uses a Japanese AMI machine to screen for health problems. 0207 499 7576 Suite 29, Harcourt House, 19 Cavendish Sq, London W1G 0PL

Biotech Health Centre – This centre uses an Asyra machine for similar screening.  01730 233414 4 Dragon Street,Petersfield GU31 4JD   Google trawl for bioenergetic screening will bring up a number of other options.

Vega testing

The Vega machine meanwhile uses a small electrode on various acupressure points to connect the patient in an electromagnetic circuit with the foods or substances to which they might be intolerant. Foods or substances which disrupt the electrical flow are deemed to be problematic.

The Vega machine is widely condemned as being unscientific and unproven – but Vega tests are cheap and have proved very popular with patients who can book a session at a high street health shop for £30-40. Testers usually have little or no medical training so there is a significant danger that serious conditions may not be recognised. That said, many of the testers are sensible, offer some sort of basic nutritional information and suggest that the test results should be validated by a two to three week elimination diet after which, if the patient does not feel any better, they should see their GP.

Although the actual results (which often come up with dairy and wheat as problematic foods) have no scientific validity, many of those who use the tests are suffering from generalised ill health which has as much to do with their lifestyle and a poor diet, high in highly refined processed foods, as it has with an allergy or an organic condition. So being forced to review their diet and exclude, for example, highly processed wheatbased products (which will probably also contain high levels of fats and sugar) for a short period, may well be of benefit to their health, as a result of which their symptoms may resolve spontaneously.

Vega machines – Most of the information available about Vega machines on the web is dismissive. However, the Da Vinci Natural Health Centre in Cyprus uses the device and gives a more balanced assessment of its possible use than we have found elsewhere. for the centre; to go to the Vega page


Any details about testing companies which appear in this article are included for the information of readers. They have NOT been paid for, and we make no recommendations as to their efficacy.

This article has been reprinted with the permission of Foods Matter, a UK magazine for food allergies and intolerances.  Find out more about their in print and online subscriptions for both the UK and the US at

About Author

Alisa is the founder of, Food Editor for Allergic Living magazine, and author of the best-selling dairy-free book, Go Dairy Free: The Guide and Cookbook for Milk Allergies, Lactose Intolerance, and Casein-Free Living, and the new cookbook, Eat Dairy Free: Your Essential Cookbook for Everyday Meals, Snacks, and Sweets. Alisa is also a professional recipe creator and product ambassador for the natural food industry.

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