Should you order one of these home “food sensitivity” blood testing kits?
Only if you want to waste your money, potentially deal with false-positive results, and come no closer to alleviating whatever symptoms were bothering you. BTW these companies don’t market this stuff as “allergy testing” but rather “food sensitivity testing” which is a huge crock of unproven pseudoscience.
David Stukus, MD, Associate Professor of Pediatrics and Associate Director, Pediatric Allergy & Immunology Fellowship Program at Nationwide Children’s Hospital and The Ohio State University College of Medicine helped fill me in on the details. Check out my prior show with him here and follow him on Twitter and Instagram, he’s an evidence-based rockstar and wonderful teacher. Some of his clinical pearls:
- Allergy tests are not ‘positive’ or ‘negative’ and by themselves do not diagnose allergies
- Allergy blood tests give a range of levels, which must be interpreted according to the clinical history
- With IgE allergy tests, 30% of people are sensitized and have detectable IgE to different food allergens but only 5-8% of people are actually clinically allergic. Testing alone will overdiagnose the vast majority of people.
- Allergies are diagnosed by taking a careful and complete medical history, which determines the pretest probability of an allergy being present, THEN using test results to help determine the likelihood of allergy
- Allergy tests have high rates of false positive results, which lead to over diagnosis and in the case of foods, unnecessary dietary avoidance and harm from restricted diets
- Allergy tests are not screening tests
- There is zero clinical indication to ever order a large panel of random allergy tests, especially to foods – these tests should only be ordered after careful consideration of the history
- There are no ‘hidden’ food allergies – if you’re eating a food without problems, you are not allergic
- Food allergy reactions cause rapid onset reproducible symptoms every time you eat that food, regardless of what form; if you’re allergic to milk, you cannot eat cheese, ice cream, etc
- Many at home tests do not even evaluate for IgE antibody, but include IgG antibodies – there is no evidence to support using IgG tests
- IgG is a memory antibody and a marker of tolerance or exposure to a food; panel IgG tests simply detect foods that have been eaten in the past, or cross reactive proteins with similar foods
- IgG tests offer bogus explanations for their results but they don’t even provide units of measurement or a range of ‘normal’ values…because they don’t exist
- Manufacturers of at home tests often tout unqualified health claims and falsely attribute food allergy or food intolerance/sensitivity with a whole random collection of symptoms that are NOT caused by foods such as fatigue, joint pain, sexual dysfunction, memory loss, etc – it’s all part of a pseudoscientific marketing scheme to get people to spend hundreds of dollars for these tests
- They also take advantage of normal human physiology – “Do you experience changes in your bowel habits, poor sleep, flatulence, etc” and turn our normal human experience into a symptom or problem that needs to be diagnosed by food intolerance testing, etc. – people need to realize it’s ok if you fart a lot after eating Mexican food…it’s all part of the fun of being a human being.
- Common example – take a real condition such as celiac disease, which can cause systemic manifestations including brain ‘fog’ or memory loss. This is a specific autoimmune condition caused by ingestion of wheat/gluten…but these websites extrapolate this real phenomenon and say ‘a wheat intolerance/sensitivity can cause memory loss, fatigue, etc – use our IgG tests to find out the cause’ and take it further to say ‘any food sensitivity can cause memory loss, fatigue, etc’
- These at home tests use the same tactics as everyone else peddling snake oil: anecdotes, B list celebrity endorsements and social media influencers, pseudoscientific explanations using catch all terms such as ‘inflammation’
Okay, everyone, yes I’m outside wearing a stethoscope because Tom made me wear a stethoscope because he wants to distinguish me from the influencers on Instagram who are tryin’ to sell you home allergy testing. Oh my gosh, the glutens are killing us!
Okay, I just found out about this thing. I didn’t know about it, and I talked to my homie Dr. David Stukus, who’s a professor of pediatrics and allergy immunology at National Children’s Hospital in Ohio, and he filled me in on this scam, okay? These guys went on Shark Tank and got a million dollars to fund EverlyWell. What EverlyWell is is a home allergy testing company, so home food allergies. So you prick your finger, you put it on these little cards, you sent it off to them, and they tell you you’re allergic to all kinds of stuff and you suddenly are woke. You’re like, “All this time I’ve had bloating and flatulence and weirdness and brain fog, it’s because of inflammation due to food allergies.” Abject nonsense.
So I’m here to tell you what’s really going on. Food allergies, true food allergies, means you eat a food and you have a pretty immediate and reproducible reaction to that food. There is no such thing as a hidden food allergy. So, real hardcore gluten intolerance, those kind of things, yes, they can cause problems, and it’s actually not that difficult to figure out because you can eliminate the food from the diet and find that your symptoms get better. So what do these home allergy tests do? Most of them are actually testing for an antibody called IgG. This is an antibody that creates a memory-immune response, which means if you’ve eaten a pear in the past, you’ve been exposed to it, and your body tolerates it and may produce this IgG antibody. It says nothing about whether you’re actually allergic to it.
So what do the actual allergists in their office actually test for? They are testing a different type of antibody called IgE, which is a more immediate allergic-type response, but even then, even then only 5% of people who actually test positive for the IgE have clinical allergies. So a lot of times you’re testing in a way that isn’t helpful, it’s producing something we call false positives, and for the doctors and others in the group, that means that your pretest probability of having an allergy has to be really high to make this test mean anything. So when you take this test at home and you get back results saying, “Brown rice, and eggs, and corn, and gummy bears. Now I can’t eat those things and I feel so much better!”
You are either denying yourself wonderful food groups because everyone knows we have a daily recommended allowance of gummy bears and now you’re not gonna get it, or you’re having a placebo effect and you’re creating a lot of fear and misunderstanding. So the bottom line is these tests are a complete waste of money. If you think you have a real food allergy see a doctor or, here’s a trick, stop eating the food, it’s called an elimination trial, and see if you still have symptoms. If you do, it probably wasn’t the food or you missed eliminating all of it, okay?
So the bottom line is if you have a friend or someone who’s sharing on Instagram, some pharmacist, or naturopath, or chiropractor, someone getting paid, probably, by one of these companies to sell you this home allergy test, and they’re saying, “Oh my God, we should get it,” you send them this video and go, “This bald clown in his backyard with a stethoscope is telling you you’re full of crap.” All right, guys? I love you. Become a Supporter if you wanna go deeper. We’re woke as heck. We out.