Direct-to-consumer urine tests are sold as proof of mold illness. In a UK biomonitoring study, a mold toxin turned up in 95-100% of first-morning samples from 79 children and teenagers who were not being investigated for mold.
If you have ever been handed a lab report with a mycotoxin name on it and a number beside it, this is the study that puts the number in context.
What they did
Maria Papageorgiou, Liz Wells and colleagues at the Universities of Hull and Leeds measured deoxynivalenol and its metabolites in first-morning urine from 40 children aged 3 to 9 and 39 adolescents aged 10 to 17 living in Hull and East Yorkshire. Samples were collected on two consecutive days from each participant, and recruitment ran from May to October 2014. The paper was published in Toxins in 2018 and is open access. It sits inside a larger European Food Safety Authority project covering 635 people across the UK, Italy and Norway.
Deoxynivalenol, DON for short, is a genuine mycotoxin. It belongs to the trichothecenes, the same chemical family that gets marketed to homeowners as the frightening one, and it is produced by Fusarium fungi growing on wheat, maize, barley and oats. Porridge, breakfast cereals, bread and malt beer all carry traces of it.
Nobody in this study was being investigated for mold. Children with acute or chronic illness, coeliac disease or gluten sensitivity were excluded. These were healthy young people eating ordinary food in an ordinary English city.
What they found
Total DON was identified in 100% of the children on both collection days, and in 100% of adolescents on day 1. On day 2 it was found in 100% of adolescent males and 95% of adolescent females: a single girl out of twenty fell below the limit of quantification. Across the whole study the authors report a detection frequency of 95-100%.
Creatinine-adjusted mean total DON was 41.6 ng/mg in the children and 21.0 ng/mg in the adolescents, a difference the authors report at p = 0.001.
219.0 against an average of 41.6. The single highest reading in the study was 219.0 ng/mg creatinine, from a female child on day 2 (214 on day 1 in the same group). The adolescent maximum was 95.6. Inside one group of healthy children, the top reading sat more than five times above that group’s own average.
The breakdown is worth a line of its own, because it tells you what the assay is actually watching. Glucuronide conjugates made up 77-88% of the total and free DON the remaining 12-23%. DOM-1, the detoxification product formed by gut bacteria, was not present in a single sample. What the lab was measuring, in other words, was the body conjugating and excreting something that had been swallowed.
The authors then estimated dietary intake from the urine levels and set it against the provisional maximum tolerable daily intake for DON, which is 1 microgram per kilogram of body weight per day. Depending on which urine-volume assumption was used, 33-63% of the children and 5-46% of the adolescents came out above it.
And urinary DON tracked what people had eaten. Total intake of foods commonly contaminated with DON correlated with urinary levels at r = 0.309 (p = 0.006); pizza on its own at r = 0.298 (p = 0.008).
Why this happens
DON is on the grain before it reaches the mill, so it arrives in the kitchen inside perfectly normal food. It is cleared through the kidneys over hours to days rather than accumulating, which means a urine sample is a snapshot of the last day or two of eating and not a running total of anything.
That is also why children read higher than teenagers here. Urinary total DON correlated inversely with height and weight, and the authors suggest the age gap comes from smaller bodies eating relatively more cereal per kilogram.
The limits, stated plainly
This is a small study: 79 people, one English city, one recruitment window from May to October. The dietary-intake figures are estimates, built on assumed urine volumes and a 72% excretion rate, and the authors say plainly that differences in estimated urine volumes “introduced great variability in the estimated intake for DON.” Dietary recall was a single 24-hour record with portions ticked as small, medium or large rather than weighed.
None of that touches the finding that matters here. DON was in nearly every sample, and the spread among healthy children was enormous.
What gets lost in the mold-testing marketing
CDC published a case in 2015 that reads like a template. A woman developed symptoms after returning to work, searched the internet, found a laboratory selling “toxic mold testing” direct to consumers, and sent in a urine sample. Her office had no musty odor and no sign of fungal growth.
The lab reported her “positive”: ochratoxin at 2.8 parts per billion against its own cutoff of 2.0, and trichothecenes at 0.4 against a cutoff of 0.2. She was referred to a clinic, diagnosed with mold toxicity, and prescribed an antifungal medication (which treats fungal infection, not toxin exposure) along with three days of canned chicken and white rice, colonic irrigation and cupping. Two consultants then removed drywall, carpet and ceiling tiles in her office and found no evidence of water damage or significant fungal growth. The cost to the building manager exceeded $25,000.
CDC, verbatim. “There is no FDA-approved test for mycotoxins in human urine.” “Mycotoxin levels that predict disease have not been established.” “Low levels of mycotoxins are found in many foods; therefore, mycotoxins are found in the urine of healthy persons.”
A CLIA certificate is not a clinical validation. Labs cite it, and it does mean something: it covers whether the laboratory runs its assay to an analytic standard. CDC is explicit that CLIA regulations “do not address the clinical validity of testing (i.e., the accuracy with which the test identifies, measures, or predicts a patient’s clinical status).”
There is no reference range. The Navy and Marine Corps Force Health Protection Command put it in one paragraph in November 2024: there are no established and validated urine mycotoxin levels that predict disease, and no reference ranges have been established for healthy populations. Except in rare acute poisonings, “mycotoxin tests reflect ingestion (food contamination) rather than inhalation.” The same factsheet notes that mold being present is not evidence the mold was producing mycotoxin.
None of this says damp buildings are harmless, and none of it says anyone is imagining their symptoms. Dampness and visible mold have solid evidence behind them for asthma, wheeze, cough and respiratory infection, which is most of what this series has been about. The point here is narrower: a number on a urine report cannot tell you that your house is the source.
What the data supports
Investigate the building. CDC’s own order of operations is visual inspection first, then a borescope inserted through a small hole to see inside wall cavities and other difficult spaces, then moisture meters on carpet, wallboard, wood, brick and concrete.
Ask any lab for its reference range in healthy people. For urine mycotoxins there is not one. That is the whole question, and it has a published answer.
Take a result to your own physician before it changes your care. Ask whether the test is FDA-cleared for the use being made of it. Antifungal drugs, elimination diets and colonics all carry their own risks.
Fix the water. CDC again: “Identification and elimination of sources of moisture and cleaning or replacement of contaminated materials is essential.” That is the intervention with evidence behind it.
Translate the geography. Nothing in this study is about Portland or Vancouver, and it makes no claim about anyone’s house. What transfers is the order of operations. If you suspect mold here, the question worth answering first is where water has been getting into the building, and that is a question about roofs, flashing, crawl spaces, plumbing and grade, answered by looking and measuring in the house itself.
None of this is medical advice, and this study makes no claim about anyone’s illness. It measured a food-borne mycotoxin in the urine of healthy children. What it establishes is narrow and still worth knowing: a mycotoxin in urine is an ordinary finding in people who were never being investigated for mold, and the level varies more than fivefold within a single healthy group. illumenair tests indoor air quality and mold in buildings. We do not test people, we do not diagnose illness, and we do not perform remediation.
Wondering whether your house is actually the source?
illumenair measures moisture and airborne mold in Portland and Vancouver homes, room by room. We test buildings, not people, and we do not remediate, so the result is not a sales pitch for the repair.
971-363-5626 · info@illumenair.com · www.illumenair.com
Sources: Papageorgiou M, Wells L, Williams C, White K, De Santis B, Liu Y, Debegnach F, Miano B, Moretti G, Greetham S, Brera C, Atkin SL, Hardie LJ, Sathyapalan T. Assessment of Urinary Deoxynivalenol Biomarkers in UK Children and Adolescents. Toxins, 2018;10(2):50, doi:10.3390/toxins10020050 (open access). Kawamoto M, Page E. Notes from the Field: Use of Unvalidated Urine Mycotoxin Tests for the Clinical Diagnosis of Illness - United States, 2014. MMWR Morbidity and Mortality Weekly Report, CDC, 2015;64(6):157-158. Navy and Marine Corps Force Health Protection Command, Urine Mycotoxin Testing, 18 November 2024.