Food intolerance blood tests have no place in the pharmacy

Imagine your pharmacy features a blood pressure measurement device. It has never worked correctly. Sometimes it give incorrect high results, suggesting hypertension. In other patients it misses hypertension completely. You’ve been advised by hypertension experts that this particular model isn’t accurate and shouldn’t be offered to consumers. Despite this, you continue to promote it to your patients, and you use the test results to recommend supplements to treat conditions that may or may not not exist.

Does this meet the professional standards expected for pharmacists? From an ethical perspective, does it respect patient autonomy?  My sense is that consumers, ethicists, regulators, and other health professionals would say “no”. Pharmacists have an ethical and professional responsibility to base advice on the best scientific evidence – in this case, to ensure that a service being offered is reliable, accurate, and relevant for making health decisions.

That’s why I’m surprised to see Canadian and American pharmacies are now selling IgG food intolerance tests. Because if you agree that knowingly offering faulty blood pressure measurement tests is unacceptable, you should have just as much concern about food intolerance blood tests. These tests have been available for some time in the United Kingdom. Now they’re in North America. Rexall, the Canadian pharmacy chain, recently started selling the “Hemocode” test which is purported to test for 250 food intolerances:

You might love food, but some food might not love you

The HEMOCODE Food Intolerance System can unlock your hidden food sensitivities

Speak with your Rexall Pharmacist today to learn about a painless blood test that can identify over 250 common foods that may be causing you unpleasant symptoms such as chronic fatigue, migraines, back pain, fibromyalgia, psoriasis, acne, diarrhea and constipation.

There’s a short video that is very illustrative.

Narrated by a pharmacist, it describes that a simple fingertip blood test is used to screen blood against 250 items. Test results are then reviewed by “naturopathic medical professionals” who will describe the foods and other products that you are intolerant to, and your degree of intolerance. You’re also advised:

Your personalized results also include recommended vitamins and supplements that are uniquely suited to the customer, based on the foods that are suggested to be eliminated from your diet, which are themselves, uniquely personal.

So the $450 blood test, includes dietary change recommendations as well as vitamin and supplement recommendation. Hemocode is an IgG blood test, according to the manufacturer (text now removed; cached version here):

The Hemocode System is a finger prick test that identifies specific immune system-based food intolerances.

Everything we eat can elicit a positive or negative reaction in the body. If you are intolerant to a certain food and you continue to eat it, your body will mount an inflammatory reaction which may manifest in a variety of lifestyle-affecting conditions such as headaches, chronic pain, digestive disorders and many other issues

The Hemocode food intolerance test is a statistically proven, doctor and pharmacist recommended IgG-related test that determines which foods are causing negative reactions.

There is no published evidence cited on the Rexall site or the Hemocode site that documents how this test have been validated. Importantly, food intolerances are non-allergic by definition. So why test immunoglobulin G (IgG)? IgG molecules mediate interactions of cells with different cellular and humoral mechanisms. IgG antibodies signify exposure to products—not allergy. IgG may actually be a marker for food tolerance, not intolerance, some research suggests:

Given the lack of correlation between the presence of IgG and physical manifestations of illness, IgG testing is considered unproven as a diagnostic agent as the results lack clinical utility as a tool for dietary modification or food elimination. So I consulted the medical literature for consensus clinical opinion on IgG blood tests, for tests like Hemocode. I summarized the literature in a lengthy post on the diagnosis of food intolerance and the use of IgG testing over at Science-Based Medicine. Here are the highlights of that review:

From the American Academy of Allergy, Asthma and Immunology & American College of Allergy, Asthma and Immunology: Allergy diagnostic testing: an updated practice parameter:

IgG and IgG subclass antibody tests for food allergy do not have clinical relevance, are not validated, lack sufficient quality control, and should not be performed.

And from the the American Academy of Allergy, Asthma and Immunology (AAAAI) Practice Paper, Current approach to the diagnosis and management of adverse reactions to foods [PDF]:

Some tests are considered unproven in regard to the diagnosis of specific food allergies. Those for which there is no evidence of validity include provocation-neutralization, cytotoxic tests, muscle response testing (applied kinesiology), electrodermal testing, the “reaginic” pulse test, and chemical analysis of body tissues. Measurement of specific IgG antibodies to foods is also unproven as a diagnostic tool.

From the European Academy of Allergy and Clinical Immunology [PDF]:

…testing of IgG4 to foods is considered as irrelevant for the laboratory work-up of food allergy or intolerance and should not be performed in case of food-related complaints.

From the Australasian Society of Clinical Immunology and Allergy (ASCIA):

There is no credible evidence that measuring IgG antibodies is useful for diagnosing food allergy or intolerance, nor that IgG antibodies cause symptoms …  Despite studies showing the uselessness of this technique, it continues to be promoted in the community, even for diagnosing disorders for which no evidence of immune system involvement exists.

From the Department of Pediatric Pneumology and Immunology, University Children’s Hospital Charité, Berlin: Unproven diagnostic procedures in IgE-mediated allergic diseases [PDF]:

The determination of specific IgG-antibodies in serum does not correspond with oral food challenges. … Since IgG-antibodies to common dietary antigens can be detected in health and disease, the determination of food-specific IgG is of no clinical relevance  and should not be part of the diagnostic work-up of food allergy.

From the Department of Paediatrics, National University Hospital , Singapore, Diagnostic tests for food allergy [PDF]:

INAPPROPRIATE TESTS :Food-specific IgG tests
Unfortunately, the determination of specific IgG antibodies in serum does not correspond with oral food challenges. … Recent studies have shown that the IgG response may even be protective, and thus prevents or protects against the development of IgE food allergy. Hence, there is no convincing evidence to suggest that this test has any diagnostic value for allergy.

From the UK House of Lords Science and Technology—Sixth Report on Allergy:

We are concerned both that the results of allergy self testing kits available to the public are being interpreted without the advice of appropriately trained healthcare personnel, and that the IgG food antibody test is being used to diagnose food intolerance in the absence of stringent scientific evidence. We recommend further research into the relevance of IgG antibodies in food intolerance, and with the establishment of more allergy centres, the necessary controlled clinical trials should be conducted. We urge general practitioners, pharmacists and charities not to endorse the use of these products until conclusive proof of their efficacy has been established.

This is just a selection of the clinical opinions on IgG food intolerance tests – see the post at Science-Based Medicine for the full summary.


At present, there are no reliable and validated clinical tests for the diagnosis of food intolerance. These tests lack both a sound scientific rationale and evidence of effectiveness.  Major allergy and immunology organizations around the world advise against the use of IgG testing for diagnosing food intolerance. These tests may lead to unnecessary and difficult dietary changes, with the potential to negatively affect nutritional status – particularly in children. So why are pharmacies offering them? Using IgG test results to guide dietary recommendations and to suggest supplements for consumers makes pharmacists look like quacks, not credible, science-based health professionals. Whether it’s ignorance of the science, or indifference to the evidence, when it comes to pharmacies selling IgG food intolerance tests, consumers are quite literally paying the price.

26 thoughts on “Food intolerance blood tests have no place in the pharmacy

  1. They are very common over here in Italy too. The UK test was advertised as the only one to be “clinically tested” but the advert did not go on to say it failed the test! (see the science based medicine post you link to).

    But they are on the market and people buy them – why? They give a nice and easy to interpret result for the doc or nutritionist – the problem is that when the patient takes action it usually involves a complete change of diet, not just eliminating a few foods. So patient changes from Dunkin Donuts diet to traditional med diet (minus “intolerant” foods) and guess what? Feels better, tells friends and family about the miracle test.

    While there is no evidence for this test (the UK company did publish a trial which was quickly debunked), there is good evidence for food intolerances. Unfortunately the only sure way to identify them is via a structured elimination diet – hard work and takes a long time…

  2. With the advent of chain stores (Walgreen’s, et al) that try to be all things to all people and are willing to sell anything that, well…SELLS, I often feel very angry about the things I see on the pharmacy shelves, but even more so, I feel embarrassed on behalf of the pharmacists who now have to work at these chains and face questions about all this snake oil day in and day out.

    The average person sees the homeopathic eye drops right on the same shelf with the rest and assumes they are genuine. After all the box says “all natural” and according to Marion Nestle (actual science-based nutrition Professor at NYU):

    “Attempts to link clean-labeling policies with the healthy eating agenda have been so successful that research now shows shoppers equate ‘healthy’ with ‘natural’ or ‘minimally processed’ foods.”

    I’ve seen any number of ridiculous products displayed right at the checkout–right in the pharmacists’ faces that is. I don’t know how they cope!

  3. when i first saw the snake oil poster i laughed. there were some duplicate medicine sellers in our place who used to say as snake oil sellers and they sell simple vegetable oil with black ingredient added to it.

  4. Heard an ad from Rexall for these tests on the radio yesterday evening. Ugh! The ad concluded with the quack miranda warning.

    Have official protests been made to Rexall, by CASS, Skeptic North, or whomever?

  5. I have not been able to find a pharmacy, either chain or independent, that doesn’t stock some sort of woo. It drives me buggy. I was a pharmacist for 12 years, and I was trained better–it appalls me that even independent stores, where the pharmacist has some choice about what to sell, offer this crap. Perhaps it is because I did my externship in what was then called an”ethical pharmacy”–one that sold nothing but prescriptions and medically-related items. We were located in a multispecialty clinic, and kept a drawer in the back full of candy and cigarettes (it was the 70’s–everybody smoked) for sale only to clinic staff, and we felt guilty about it. At least we weren’t trying to pass it off as healthy.

    • It seems that ethics have gone the way of cigarettes (for most) and cooking real food at home. It’s hard for me to see how anyone who spent as long on an education as a pharmacist, would want to be reduced to working in a chain drugstore. I suppose, like the most of the rest of the population, they have little choice in the matter. What happens when a whole generation of young people have to put ethics aside in favor of making a living? Talk about “working for the man”!

      Sometimes, I’m not that sorry that I won’t be around to see the eventual fallout from all this. I’d like to see some work done on how many people really are being hurt by such practices–many assume there is really no harm in it, but I’m not so sure having known several people who did not see a doctor until their cancer was Stage IV because they preferred (fill in the blank) woo.

  6. Thank you for this informative post! I was all set to hit Rexall as I suffer from a variety of annoying symptoms that are at an all-time high today. Ugh! Feeling awful… Glad I found this info. Thanks again.

    • Please note that tests such as this one take money out of the largest corporations in the world, the pharmaceutical and medical companies. So they will go to the ends of the earth to make you believe they won’t work! It’s a harmless test. A little blood, some info on what foods your body doesn’t like, you remove those foods and you either feel better or not. If you see no results in a month or so, you go back to how you used to eat, but I have yet to meet someone who has actually tried a test like this (usually done through a naturopath though) and didn’t improve their overall health! My friend no longer is classified with fibromyalgia. My daughter no longer wakes up screaming and has blood in her stool. My son is no longer seen as autism spectrum or ADHD. Just with diet changes…

      • Please note that tests such as this one take money out of the largest corporations in the world, the pharmaceutical and medical companies. So they will go to the ends of the earth to make you believe they won’t work!

        Evidence please. Interestingly, it isn’t “pharmaceutical and medical companies” that state these tests are ineffective, it is every major allergy and immunology organization in the world which have actually looked at the tests.

        These tests are not “completely harmless.” They identify “intolerances” which don’t exist, suggesting dietary changes which may be completely unnecessary. The potential for dietary changes, which can result in deficiencies is real. In addition, people may have genuine medical issues that they believe are being addressed by tests which don’t give validated results. Not to mention the harm they do to your wallet – the tests run about $400.

        Interestingly the Advertising Standards Authority upheld a complaint this week about the YorkTest:

        A direct mailing for FoodScan food intolerance testing. It included several customer testimonials, including “Hyperactivity Five year old Michael used to be so hyperactive that he could only go to school on a part-time basis … After taking the FoodScan 113 Test Michael discovered he was intolerant to a range of foods …

        and subsequently noted the following:

        The ASA noted YorkTest did not submit evidence to demonstrate that the testimonials in the ad were genuine or to substantiate the efficacy claims made in the testimonials. In the absence of such evidence, we considered the testimonials had not been demonstrated to be genuine and that the efficacy claims were misleading. We therefore concluded that the ad breached the Code.

        The ad breached CAP Code (Edition 12) rules 3.1 (Misleading advertising), 3.7 (Substantiation), 3.45 and 3.47 (Endorsements and testimonials) and 12.1 (Medicines, medical devices, health-related products and beauty products).

      • Fibromyalgia is not able to be cured by dietary changes, and people are not “classified” with it. it is a real illness, that often responds well to “Big Pharma” products like Cymbalta, and people are *diagnosed* with it. I’m glad your friend is better, but if she is because she changed her diet, then she never had fibro to begin with.

        Similarly, ASD and ADHD are not curable by dietary changes. If it were that simple and easy, millions of people would know about it by now and millions would be “cured.” Just because the illnesses you’ve chosen don’t have actual cures does not mean we don’t know anything about them, and one thing we absolutely do know is that none of them are fixable by correcting a food insensitivity.

        It’s actually quite insulting to people who are in fact disabled by fibro, or struggling on the ASD, to imply that if they just stopped eating x, they’d be fine. As someone disabled by an illness you didn’t mention but is almost always included when people claim the kind of things you are claiming — these are real people suffering from sometimes crippling problems who, I assure you, have already tried EVERYTHING (including dietary changes) possible to be as functional as possible.

  7. Thank you for this. But we have to recognize that quackery proliferates when science has little or nothing to offer; there comes a point when you are willing to try anything for relief. For months, I had alarming heart symptoms and every physician I saw was obsessed with my cardiac health until my family doctor asked: “You wouldn’t be celiac, would you?”, despite my lack of traditional symptoms. Eliminated gluten and casein, problem essentially solved – but no official diagnosis yet.

    • “there comes a point when you are willing to try anything for relief.” I do not believe so: people do retain some rationality. If I told someone to cut off their hand to relieve their headache, I doubt many would comply. I think people are susceptible to anecdotes, and do not have enough training in science, medicine and logic to evaluate the cures propounded by quack health “experts”.

      I regret I find I cannot believe your own anecdote.Your doctor is suspect: asking if you had coeliac disease in response to your cardiac symptoms makes no sense, since cardiac problems are not indicated for coeliac disease! And casein has nothing to do with it either. Unless you are speaking of a naturopathic “doctor” or “nutitionist”, in which case I fully understand, since cutting gluten and dairy is their typical non-scientific response: .

      • Art Tricque, I am consulting a physician, not a nutritionist. His suggestion was obviously no more than a hunch, based on past experience with a couple of patients having unexplained symptoms. After a series of tests, nothing was found to explain my problem, so I tried and I feel better. As you indicate, it is anecdotal. I have no idea yet whether or not I am actually gluten-intolerant. After several months, I am, however, satisfied that my heart rate doesn’t shoot up to 180 anymore with no reason, and that I am no longer belching continuously for hours on end. And a proper gluten and dairy-free diet, though inconvenient, can be very healthy.

        Your skepticism is understandable, but it seems to be based on the premise that science has all the answers about celiac disease, which is obviously false, as is the case for many autoimmune disorders. Which brings me back to my initial point: Yes, let us denounce quackery such as those tests sold in pharmacies, but let us also recognize it when denunciations are all we have to offer, and nothing else, to help those who are afflicted with misunderstood disorders.

  8. Tests of this nature are completely harmless. You take the test, they say “try taking these foods out of your diet.”. You try it and you either see improvement or you don’t. But regardless of whether science can “prove” it or not to be accurate, everyone I know who has done such a test has seen tremendous results, including myself. My medical dr for my children, when I brought up gut pain and blood in my daughter’s stool did a general blood test. (she’s 3 and while she was tough, drawing blood isn’t fun). Nothing came of it. Had to do a second round of bloodwork, testing for celiac disease. Nothing came of THAT! Second time was much less pleasant. Next they wanted to scope her. I did some research and tried one of these food intolerance tests. Turns out dairy is the main culprit with a few other foods. Changed her diet and she’s all better. Decided to test my son. Was told by medical professionals that he needed psychiatric assessment. He was being checked for ADHD, aspergers, OCD. Changed his diet according to test results and he’s just an average little boy! So bash the testing credibility if you wish, but I would suggest you try it first.

    • Above you say “My son is no longer seen as autism spectrum or ADHD.” But according to this he never had a diagnosis of anything at all that was “cured” by changing his diet.

      This is, incidentally, exactly what happened with Jenny McCarthy. She claimed dietary changes cured her (never actually) autistic son after first claiming it was vaccines. She successfully managed to lower vaccination rates across the country, inviting numerous epidemics of vaccine-preventable disease and causing countless morbidity and mortality. (People becoming sick and dying, usually children.)

      If you’re going to tout an amazing cure, you might try 1. to be open and honest about your experiences and not exaggerate or misstate them as you have, 2. throw your lot in with someone who isn’t roundly seen as a menace to public health.

      • I am being open an honest. My son has been seeing psychologists and what did they want to do??? Here’s a prescription!!! I took matters into my own hands and now have a happy socially functionable little boy! And the change from being mostly in his own world with temper tantrums and never wanting to do anything that was new, to a happy, outgoing, boy who clearly communicated and almost never had a tantrum was a matter of days.

        And where is your source of information about Jenny McCarthy causing massive outbreaks of preventable diseases…. Anyone can write anything they want on the net and the pharmaceutical companies do just that to try to keep people paying for drugs. And they have enough money that they can even pay news casts to say whatever they want them to say to make it look like fact! You never see an hour of news without half a dozen drug commercials (cause they are sponsoring the news cast). They have complete power! So who’s being duped here??? You keep shoving money into their pockets and they will keep feeding you lies to make you believe natural stuff just can’t work! They WANT you to be sick, and they want you to believe that the only way to be healthy is to use a drug. They actually made it illegal in the USA to say that anything other than a drug can cure, treat, or prevent a disease. You are breaking the law if you say “oranges cured my scurvy” food and drug companies have all the power and they have no problem sacrificing your health to keep it!

      • Conspiracy theories and the naturalistic fallacy.

        I urge you to read the article above and the references. Sadly, the only ones being duped are those buying IgG food intolerance blood tests.

  9. Did any of you actually read the post, and consider what Scott is saying? IgG is a USELESS marker to measure food intolerance. Studies are beginning to show that it may actually be useful as a marker for developing tolerance in those previously allergic to the food. By all means, eliminate foods you think are suspect – but don’t base the decision on which foods from this test! You are all being duped, and this is one of the many reasons that there is an “explosion” in food allergies – most are not being diagnosed by allergists at all, and more and more people are claming allergies to something – muddying the waters for those that are at risk of anaphylaxis. Anyone proclaiming an allergy to a food needs to see an allergist to confirm it, it is a complex process that no other health care practitioner is qualified to conduct. If you meet one that says they can, run away.

  10. The TRUTH is there is no black or white answer here. I’m not for or against these tests, but the fact that they haven’t been proven to work scientifically isn’t enough prove that they are some sort of scam. Basically, it’s a 450 dollar gamble….I believe 100 percent that some people may get some good guidance from these tests, but I’m far from believing that they are foolproof. It is a little shady to have them in pharmacies though…makes it seem like Hemocode has the full support of the medical community

    • It’s important not to confuse situations where there are unanswered questions about efficacy, with a situation where something has been studied and important efficacy questions have been answered. In the case of IgG tests, vendors have provided no evidence their specific tests are effective. So we look for other studies with IgG. What tests using IgG show is that they always give positive results, because IgG is a normal immune responses to food. See IgG Food Intolerance Tests: What does the science say? for more detail.

      I agree with your comment regarding the sale in pharmacies. Over at Science-Based Medicine, Jann Bellamy raised the comment as to whether a health professional who is directly selling this type of test has an legal or ethical responsibility to disclose scientific implausibility and lack of efficacy. I would argue “yes” to both questions.

      One of the most perplexing issues with unvalidated laboratory testing is that regulators like the FDA get justifiably upset when pharmaceutical companies promote and sell drug products for unapproved uses – look at the $3 billion dollar fine that GlaxoSmithKline has recently agreed to pay for this behaviour. Yet regulators seem to be indifferent when a blood test promoted and sold where there is no published evidence demonstrating it is effective – and there is published information suggesting these tests are ineffective.

  11. Just 50 years ago mothers were being blamed for their childrens autism, because of being emotionally detached. Only 75 years ago doctors advertised smoking. The medical community doesn’t know everything. They are not “God”. Of course diet affects people – who would be stupid enough to think it doesn’t!? Maybe Hemocode is a bunch of malarky, but I’m not going to take the medical industry’s word for it until they remove it from the market. If it’s as dangerous as claimed above (people hurting their bodies by drastically changing their diets) then I have no idea why it isn’t under severe investigation. Sounds to me like it may not be as far fetched as they are putting it out to be. Many Doctor’s who find out a woman is seeing a midwife for her pregnancy will go on and on talking about the dangers associated with that – and that is utter nonsense as many of us can tell you. Doctor’s tell you co-sleeping is dangerous, but what they don’t tell you is that babies who co-sleep have lower incidences of SIDS and that the “danger” only lies in the parent being intoxicated or an extremely heavy sleeper (which I think most can agree that most parents pretty much sleep with one eye open for the first three months at least). They also don’t tell people that “SIDS” is an umbrella term that refers to diseases or disorders that haven’t yet been discovered. Babies don’t just die.
    Some food intolerances are far worse than food allergies. My daughter suffers from Encopresis which, till recently, we had no idea was related to a severe food intolerance to Casein and Food Dye’s. It was our allergist who did an IgE test on her and discovered she wasn’t allergic that told us that the proof was in the elimination diet we tried and that she should not consume casein or food dye and should probably start avoiding gluten and soy. An allergist – yes people, a trusted member of the medical community. My daughter also has ADHD and I absolutely believe that removing things that her body considers toxins while adding things that her body needs more of will help her with her ADHD. No, ADHD cannot be cured – I know, I have ADHD. But as an adult who deals with this I can honestly say that of course diet affects it. And of course diet can improve it. As with anything in life. And exercise – that helps too. A medical professional told me that folks – though there hasn’t been any clinical testing on exercise and ADHD.
    Did you know that adults who have ADHD but don’t know it are often heavy coffee drinkers because the caffein acts as a stimulant for their brain – in turn helping them focus and concentrate? True fact. Food for thought. 😉

    Here is a good read written by a medical proffesional:

  12. why are you such a hater scott? If someone is saying this helped them or their family…then guess what…that’s EVIDENCE!!!!!!!!

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