MycoTOX measures 11 mycotoxins in a single first-morning urine sample. It shows exposure, most of which comes from food, and it doesn't diagnose mould illness. I no longer offer it for mould at home. This page explains why, what a result you already have can tell you, and what to do instead.
If you can see mould, smell damp or have had water damage, fix the source before you think about a test. A urine test can't tell you whether your home is damp; a surveyor or damp specialist can. NHS inform's advice is to find out why there is too much moisture in your home, and it notes that moulds produce allergens and can trigger asthma attacks (NHS inform, damp and mould indoors).
If you rent, report damp and mould to your landlord in writing and keep a copy. In Scotland, from 6 October 2026, social and private landlords must investigate a report of damp or mould within 10 working days, give you a written summary within 3 working days of finishing, and start repairs within 5 working days where they're needed. Social landlords must finish within 20 working days; private landlords "as soon as reasonably practicable" (Scottish Government, Awaab's Law guidance). Shelter Scotland also has advice for renters.
See your GP rather than ordering a home test if you have asthma, allergies, a chest condition or a weakened immune system and you live with damp, or if you have breathlessness, wheeze or chest infections that keep coming back.
It’s widely sold for exactly this, and I used to sell it. I stopped for three reasons. Most mycotoxin exposure comes from food, so a high result can’t be pinned on your house. No study validates a urine level as a diagnosis of mould-related illness, and the German multi-society guideline on indoor mould says the test shouldn’t be used for that (AWMF guideline, Hurraß 2024). And the decisions people make on a result are big ones: moving house, expensive remediation, months of binders. A number that hasn’t been validated shouldn’t drive those.
What does have evidence is the building itself: damp and visible mould are consistently linked with asthma, wheeze and chest infections, and fixing them is the step that helps (Mendell 2011). That’s where your money is better spent.
MycoTOX is Mosaic Diagnostics' (formerly Great Plains Laboratory) urine mycotoxin profile. It’s available through UK distributors such as Nordic Laboratories. It measures 11 mycotoxins, which the lab says come from about 40 species of mould, using liquid chromatography–tandem mass spectrometry (LC-MS/MS) on a first-morning urine sample.
Mycotoxins are chemicals made by some moulds. They are not the mould itself. Most people's exposure comes from food: cereals, nuts, coffee, dried fruit, spices and milk can all carry small amounts. Damp, water-damaged buildings are a second possible source.
Most people have some mycotoxins in their body, and most of it comes from food. In a Dutch biomonitoring study, deoxynivalenol and zearalenone (from cereals) were found in the urine, and ochratoxin A in the blood, of every one of 36 pregnant women tested, at levels judged of low concern (McKeon 2024). So a detectable level is expected. On its own it doesn't show that your home is damp or explain your symptoms.
The lab's reference ranges are its own. I haven't found a published study that validates a urine mycotoxin level as a diagnosis of mould-related illness. The German multi-society clinical guideline on indoor mould goes further: it says urine and blood mycotoxin testing has no place in diagnosing people exposed to indoor mould and shouldn't be done (AWMF guideline, Hurraß 2024). That, together with the food problem above, is why I no longer offer it for mould at home. A result is most useful alongside the history (a damp home or workplace, symptoms that ease when you're away from it) and as a baseline to retest after the source has been dealt with.
Grade: a measure of exposure, reasonable. A diagnosis of illness: not validated.
The panel list below is the lab's. The moulds and usual sources are from standard references; where exposure is mostly from food, the table says so.
| Mycotoxin | Made by | Where exposure usually comes from |
|---|---|---|
| Aflatoxin M1 | A breakdown product of aflatoxin B1 (Aspergillus) | Food: milk and dairy for M1; grains and nuts for B1 |
| Ochratoxin A | Aspergillus, Penicillium | Food (cereals, coffee, dried fruit, wine); also damp buildings |
| Sterigmatocystin | Aspergillus (e.g. A. versicolor) | Damp buildings; some grains and cheeses |
| Zearalenone | Fusarium | Mostly food: cereals |
| Enniatin B1 | Fusarium | Mostly food: cereals |
| Citrinin (measured as dihydrocitrinone) | Penicillium, Aspergillus, Monascus | Food (cereals); also damp buildings |
| Roridin E | Stachybotrys and related moulds | Water-damaged buildings |
| Verrucarin A | Stachybotrys and related moulds | Water-damaged buildings |
| Chaetoglobosin A | Chaetomium | Water-damaged buildings |
| Gliotoxin | Aspergillus fumigatus | Buildings and the outdoor environment; also made during Aspergillus infection |
| Mycophenolic acid | Penicillium | Food and buildings. It is also a prescription drug (mycophenolate, used after transplants and in autoimmune disease), so anyone taking it will test positive |
Some of these are well-established hazards at high exposure, almost always through contaminated food. Aflatoxin B1 can cause liver cancer in people, and Europe's food safety authority treats current aflatoxin intake as a health concern for some groups (EFSA 2020, aflatoxins). Ochratoxin A damages the kidneys in animals; EFSA judged dietary exposure of low concern for most people, with high uncertainty (EFSA 2020, ochratoxin A). For most of the others, the evidence comes from cell and animal studies. Whether the low levels usually found in urine cause symptoms has not been shown.
What's supported: damp and mould can cause allergic symptoms (sneezing, a runny nose, red eyes, a skin rash) and trigger asthma attacks, and NHS inform notes they can affect the immune system (NHS inform). Breathing problems in a damp home are a reason to see your GP.
What people also report, often in connection with mould: fatigue, brain fog, headaches, poor sleep, muscle and joint aches, gut symptoms and new sensitivities to food or chemicals. These are real symptoms with many possible causes. I haven't found good evidence that they are caused by the mycotoxin levels found in urine, so a urine result can't confirm that mould explains them. Grade for mycotoxins as the cause of these symptoms: none.
Plenty of people arrive with a MycoTOX or similar report already done. Here’s how I read one.
Finding and fixing the source matters more than the test. These are the questions I ask:
The first step is a qualified surveyor or damp specialist to find the moisture source and fix it. Laboratory tests of dust or air can identify which moulds are present, but I haven't found evidence that their results predict health effects. You don't need one to justify a repair.
Some organic acids tests list “Aspergillus” or “Fusarium” markers. I haven’t found a study validating any of them against measured mould exposure, and at least one comes mainly from food. 5-hydroxymethyl-2-furoic acid is the breakdown product of HMF, which forms when sugars are heated: in 53 people, coffee, dried fruit, honey and alcohol predicted the urine level (Husøy 2008), and it has been proposed as a marker of coffee drinking (Rådjursöga 2017). Tricarballylic acid is part of the fumonisin molecule, but nothing shows the urine level tracks fumonisin exposure. Grade for OAT markers as a sign of mould exposure: none. I don’t read them that way.
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