Food Sensitivity and Gut Barrier Test

What this test actually measures

There are several completely different things people mean by a food reaction, and they get confused constantly, so it is worth separating them before anything else.

A food allergy is IgE mediated. It happens fast, it can involve the airway, and it can be life threatening. That is not what this test measures, and it is not what this test rules out.

Coeliac disease is autoimmune, triggered by gluten, and it damages the intestinal lining. That has its own specific serology and it must be tested while you are still eating gluten. Also not this test.

A food intolerance is a digestive capacity issue, like lactose intolerance, producing gas and discomfort rather than an immune response.

This test measures IgG and immune complex reactivity, which is a different immune pathway from allergy. It also includes a gut barrier panel, assessing markers of intestinal permeability, which is the more mechanistically interesting half of the result.

How to use this well, and how people use it badly

I want to be straightforward about the evidence here, because food sensitivity testing is one of the more contested areas in this space and you deserve the honest version.

IgG antibodies to foods are, in part, a normal record of exposure. Your immune system makes them in response to things you eat, and finding them does not automatically mean those foods are causing symptoms. Several allergy societies have argued against using IgG testing to diagnose food intolerance for exactly that reason.

So what is it good for?

It generates a shortlist. If you have persistent symptoms and no idea where to start, a panel like this narrows 176 candidates down to a handful worth actually testing on yourself, which is considerably better than eliminating at random.

The test that produces the answer is still the elimination and reintroduction, done one food at a time, with a deliberate reintroduction to confirm. That is what tells you whether a food matters for you. The panel just tells you where to look first.

Used that way it is genuinely useful. Used as a list of foods to avoid permanently, it is how people end up eating twelve things and no better off, which is the outcome I most want you to avoid.

The gut barrier half of the panel is worth more attention than it usually gets. Reactivity to many foods at once frequently says more about barrier function than about the foods themselves, and if that is the picture, the productive work is upstream. A 2025 review in Nutrients described how bacterial and fungal overgrowth in the small intestine produce malabsorption and inflammation, which is one route by which barrier function gets compromised.

One sequencing rule that is not optional. Get coeliac serology before you remove gluten, because removing it first makes the test unreliable and coeliac disease carries risks and follow-up that a sensitivity does not.

Test details

What is measured: IgG and immune complex reactivity across 176 foods, plus markers of intestinal barrier function.

Sample: finger prick.

Provider: KBMO Diagnostics, ordered through Jess's practitioner dispensary.

Fasting: not required. You do need to have been eating a normal varied diet, since removing foods beforehand can lower the reactivity being measured.

Turnaround: results typically within a few business days of the sample reaching the lab.

Order this test.

How the pricing works

I want to be straightforward about this, because lab pricing in the wellness industry frequently is not.

Jess takes no markup on the test itself. The lab cost is passed through exactly as it comes. What you pay is the test cost, the dispensary's service fee, the authorization fee, the collection fee where one applies, a flat handling fee for placing and managing the order, and the card processing cost. The handling fee is the part that is Jess's, and it is flat regardless of how expensive the test is.

That structure is deliberate. A percentage markup on labs creates an incentive to recommend expensive tests, and this way there is not one.

The full lab menu shows everything available, and the order page itemises every fee before you pay.

Who this test is worth running for

Anyone with persistent gut symptoms, skin flares or unexplained fatigue that seems to track with eating but without an identifiable pattern, and who wants a starting point rather than a random elimination.

It is most useful for people who have already tried removing the obvious suspects without a clear answer, because that is exactly when a shortlist is worth having.

It is the wrong test if what you actually need is allergy testing, which is a different pathway and belongs with a doctor, or coeliac serology, which must come first and must be done while eating gluten. And it is a poor first choice if your bloating arrives within an hour of eating, since that pattern points at small intestinal overgrowth and needs breath testing rather than a food panel.

Ordering restrictions

The lab network cannot issue orders to residents of New York, New Jersey, Rhode Island, or Hawaii. New York, New Jersey, and Rhode Island prohibit direct-to-consumer lab testing outright, requiring a treating provider's signature on every requisition. Hawaii is excluded by the network. This is tied to where you live, not where the sample is collected, so it applies to kits as well as draws.

If you live in one of those four states, your doctor can order the same test.

What to do with the result

Treat the reactive list as a shortlist, not a verdict. Pick the highest-reacting one or two foods and test them properly rather than removing everything flagged.

Remove one food at a time for two to four weeks, then deliberately reintroduce it. The reintroduction is the part that produces the answer, and skipping it is how people end up with a permanently shrinking diet and no information.

Read the gut barrier markers seriously. Reactivity to many foods at once often says more about barrier function than about the foods, and if that is your picture, working upstream is the productive move.

Do not remove gluten before coeliac serology. If you have never had it, get that first, while still eating gluten.

Take the report to someone who reads it alongside your symptoms. A good functional medicine doctor, ideally with a dietitian involved if multiple foods are in play, since that is how you avoid over-restricting.