Mycotoxin Test Results: What the Number Can and Cannot Prove

A positive mycotoxin test shows compounds almost everyone carries, mostly from food, and little more. No urine mycotoxin test is FDA-approved, and none has a healthy reference range. So the number cannot be called high. The repairs with human data are fixing the damp building and, where aflatoxin comes in food, a tested clay given under supervision.

A urine panel came back positive twice over. Ochratoxin read 2.8 parts per billion against the lab’s line of 2.0. Trichothecenes read 0.4 against a line of 0.2. A crew then stripped drywall, carpet and ceiling tiles from the building. They found no water damage and no significant fungal growth. It cost the building manager more than twenty-five thousand dollars.

That is the whole problem with the mycotoxin test as usually sold. It is a measuring problem, not a biology problem. The compounds are real. The number on the report has nothing standing under it.

I am Dr. Gurpreet Singh Padda, MD, MBA, MHP, coauthor of The Angry Gut with Ami Michelle Grimes. In the video Mold Illness: Fix the Basement, Skip the Panel, I rank the mold claims by strength of evidence. The question here is narrower. What can a mycotoxin result prove about your terrain, and what should you repair instead of measure?

Is mycotoxin testing legitimate?

A lab value means something only when compared with healthy, unexposed people measured the same way. These panels supply none. There is no FDA-approved test for mycotoxins in human urine. A 2024 European guideline finds no useful validated method for clinical diagnosis. American medical toxicology rejects the antibody versions as well. A number without a reference range is neither low nor high. It is simply printed.

Presence versus dose: what a real measurement looks like

The version that means something came from a pregnancy study, not a mold clinic. Fifty pregnant women at one academic center were sampled at four points. Their blood and spot urine were analyzed by mass spectrometry. Repeat sampling matters because these compounds clear fast, so one urine sample mostly reflects recent meals.

Almost everyone carried something. Blood citrinin appeared in 32% of samples at a median of 0.02 ng/mL. Urine alternariol monomethyl ether showed up in 69%, and zearalenone in 63%. Aflatoxin, the compound with the worst reputation, was not found in any sample.

Then intakes were compared with published safety limits. On average across the sampling points, 28% of the women went over the tolerable daily intake for deoxynivalenol, and 2% for zearalenone. Against the human biomonitoring guidance value, deoxynivalenol went over in 48%. Every sample with measured ochratoxin A had a margin of exposure for cancer effects below 10,000, a flag for possible concern. That is a head count turned into a dose. Its limits: pregnant women, food as the route, no health outcome measured, and not one damp basement.

Where do the mycotoxins in your body come from?

The 2025 American toxicology position names diet as the biggest source of mycotoxin exposure. It models inhaled doses in moldy buildings at levels hundreds of times or more below harmful thresholds. So a urine result is partly a record of what you ate, and grains carry most of it. Read any single number as a blend of plate and place.

The terrain argument sits under that. Mycotoxins damage the gut barrier across its physical, mucus, immune and microbe layers. That has been shown mainly in cell and animal models. In Nigerian infants, stool mycotoxin levels tracked with gut microbe makeup. Which compounds showed up depended on whether stool, urine or breast milk was sampled. The barrier is where the first brain meets the outside world, and metaflammation starts at that wall long before a lab names a toxin.

The markers sold with the diagnosis

The framework behind these panels adds a blood picture: low alpha-melanocyte-stimulating hormone plus a rise in at least one of TGF-beta 1, C4a and MMP-9. To its credit, that can be tested. Outside the group that created it, it is neither confirmed nor disproved.

The biology it borrows is real. MSH calms the fever and inflammation effects of cytokines, and it cut endotoxin-driven IL-1 and TNF in whole blood. But it moves wherever illness moves. It goes up in healthy volunteers given endotoxin and down in sepsis. It runs higher in advanced HIV and in the more inflamed arthritis. It is lower in healthy older people than in the young. No reference interval, assay standard or cross-lab comparison exists. A value with no normal range behind it cannot be called low.

In the main cholestyramine trial, MSH was abnormal in 25 of the 28 who consented. The allergy marker IgE was abnormal in just 1. And MSH was never measured again after treatment. The supporters’ own 2024 review counts ten papers from one group and two randomized trials of 8 and 13 subjects. It claims the illness can affect up to 25% of the population. That is a risk estimate with no confidence interval. And two of its three authors testify as expert witnesses in these cases.

The incentives are easy to trace. A panel, a protocol and a lawsuit can each be billed. Drying a foundation is a cost the landlord would rather put off. Follow the invoice and you can predict which claims get marketed and which repair gets postponed.

What earns its place: the clay, then the building

Here the tiers flip. In Ghana, 177 people at high risk of aflatoxin in their food were randomized to 3.0 g or 1.5 g of calcium montmorillonite clay, or placebo, daily for three months. More than 97% took it as told. Nothing differed at one month. At three months, blood aflatoxin-albumin adducts fell in both dose groups. Urine aflatoxin M1 fell by up to 58% at the high dose. Blood vitamins A and E stayed about the same. The same clay cut urine fumonisin B1 by more than 90% at the high dose in humans.

Read that as narrowly as the authors did. The clay cut the absorption of aflatoxin being eaten. It did not show clearing of anything stored. And it was a tested, contaminant-screened clay given under supervision, not a store-shelf detox product. Cholestyramine binds bile acids, and the bile circuit it interrupts is not proof a toxin was riding in it. Anyone already taking it should raise the question with the prescribing physician, not change course alone.

The building is the repair with human outcome data. A Cochrane review pooled 12 studies and 8,028 people. It found moderate- to very low-quality evidence that repairing mold-damaged homes and offices reduces asthma symptoms and respiratory (breathing-tract) infections in adults. One included study found no difference between full and partial repair. No study collected a gut outcome. Fix the wall anyway.

What should you do instead of a mycotoxin test?

The best tool is already yours. Record dates, not impressions. Note when symptoms shift, where you slept, and what changed in the house beforehand. Pollen can mimic a building on a seasonal calendar, so the dates matter. Then measure what repair can move. A metabolic audit tests whether your body can heal, testing before treating keeps each number tied to a decision, and rebuilding the gut after antibiotics is the next terrain problem. Every study cited here is in the Deep Dive, with full numbers and what each one does not show.

Frequently asked questions

Are urine mycotoxin tests FDA approved?

No. There is no FDA-approved test for mycotoxins in human urine. The lab rules these panels run under do not check whether the test measures what it claims. European and American specialty groups both say the available tests are not validated for clinical diagnosis. A result still gets printed, just without a healthy reference range. The mold diseases that are firmly established are immune ones, diagnosed differently.

What does a positive mycotoxin test mean if everyone has them?

On its own, very little. Low levels sit in ordinary food, and so in healthy urine. A positive only means a value landed above a cutoff somebody chose. The useful version compares estimated intake with a published safety limit. That is how the pregnancy study showed who stood over the line. How an inflammation biomarker earns clinical meaning shows the standard these panels miss.

Do mold binders remove mycotoxins from the body?

The best binder evidence is a clay trial in Ghanaians eating food tainted with aflatoxin. Exposure markers fell at three months without draining vitamins A and E. That shows less absorption of a toxin being eaten, not removal of a stored one. And the trial clay was a tested product. Why one treatment works in one terrain and fails in another applies here too.

Is MSH a reliable marker for mold illness?

Not yet. Alpha-MSH can be measured and is biologically real. But it rises with endotoxin, falls in sepsis and drifts lower with healthy aging. So a single value has no fixed meaning. No reference interval or cross-lab standard has been published. That makes a low reading an opinion about a number. Inflammaging explains why so many inflammatory signals drift with age.

Does mold remediation improve gut health?

Nobody has measured it. The controlled repair trials scored wheeze, runny nose, asthma days and infections. None collected a gut outcome. The study that would answer it would randomize houses, not patients, and measure calprotectin and flare rates. Until then, repair rests on airway data and on a precaution every guideline shares. What refills a gut from above is the next place to look.

How do I test my body for mycotoxins?

A single urine sample mostly reflects your last few meals, because these compounds clear fast. The version that meant something sampled blood and urine at four points. It used mass spectrometry and compared estimated intake with published safety limits. For a suspected building, the stronger record is your own. Note the dates of symptom changes, where you slept, and what changed in the house beforehand.

Which foods are high in mycotoxins?

Food, not the building, is the main source of mycotoxin exposure, and grains carry most of it. In a group of pregnant women, 28% on average took in more deoxynivalenol than the tolerable daily intake. That is why a urine result is partly a record of what you ate. Read any single number as a blend of plate and place.

Sources

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Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP, board certified in anesthesiology, pain medicine, interventional pain management, addiction medicine and obesity medicine. Adapted from Chapter 26 of The Angry Gut by Dr. Padda and Ami Michelle Grimes. Last reviewed September 2026.