What A Positive Mycotoxin Result Could Mean For You

A positive mycotoxin result tells you that your body has been exposed to one or more mycotoxins, the toxic compounds made by some moulds. It does not tell you that you have an illness, and it does not tell you where the exposure came from.

Key takeaways

• A positive mycotoxin result means a mycotoxin was found in your urine above the lab’s reporting cut-off. It shows exposure, not illness.
• Most people have some mycotoxins in their urine. In a UK study of 29 young children, 99% of 114 urine samples contained at least one [1]. In UK adults, deoxynivalenol alone was found in 296 of 300 urine samples [2].
• Food is the main source for most people. Damp or water-damaged buildings are another possible source.
• A growing body of research links mycotoxins with chronic conditions such as ME/CFS, autism and Parkinson’s disease, and with effects on the gut, immune system and mitochondria. Much of it is early-stage, but it is building.
• Levels that predict disease have not yet been established, and urine mycotoxin tests are not approved as diagnostic tests [3]. That is why expert interpretation matters.
• Your result is most useful when it is read alongside your symptoms, your home and work history, and your diet.
• Sensible next steps are a practitioner review, a check of your home for damp, and support for your gut and overall health.

Opening a report that says “positive” can be unsettling. You may have taken the test because you feel unwell and suspect mould. This guide explains what your result could mean for you. It covers what the test measures, where mycotoxins come from, what the common markers mean and the practical steps that make sense now.

What does a positive urine mycotoxin result measure?

A positive result means the lab found one or more mycotoxins, or their breakdown products, in your urine above its own cut-off. That cut-off is a detection or reporting line. It is not a health threshold.

Labs usually use liquid chromatography with tandem mass spectrometry (LC-MS/MS). This is the method of choice for measuring several mycotoxins at once in urine, and it can detect very small amounts [4]. Results are usually adjusted for creatinine, a waste product that corrects for how dilute your urine is [4]. This makes samples easier to compare.

Does a urine mycotoxin test show recent or past exposure?

For most mycotoxins, urine levels mainly reflect what you ate in the last day or two. In a UK study of young children, urinary deoxynivalenol was most closely linked to cereal intake on the same day as the sample [1].

Ochratoxin A is the main exception. It stays in the blood much longer, with an estimated half-life of about 35 days, measured in a single volunteer [5]. So an ochratoxin A result can reflect exposure over several weeks.

This is why Healthpath asks you to follow a low-mould diet for about three days before testing. It aims to reduce the effect of recent meals, so your result is more likely to reflect ongoing or environmental exposure.

Does a positive mycotoxin result mean you have mould illness?

Not on its own, but it can be an important piece of the puzzle. A positive result shows exposure. When it is read alongside your symptoms and your home and work history, it can help you and your practitioner decide whether mycotoxins are likely to be playing a part.

Context matters because mycotoxins are common. A UK study collected 114 urine samples from 29 young children eating their normal diet. Deoxynivalenol was found in about 96% of samples and ochratoxin A in about 89%. Only 1% of samples had none of the toxins tested [1]. In a separate study of 300 UK adults, deoxynivalenol alone was found in 296 urine samples (99%) [2]. Modelled data from large European studies show widespread exposure in adults too [6].

So the key question is not just whether a mycotoxin is present, but how much, which ones and whether they fit your wider picture. The US Centers for Disease Control and Prevention (CDC) notes that mycotoxins are found in the urine of healthy people. It adds that levels which predict disease have not yet been established, and that urine mycotoxin tests are not approved by the US Food and Drug Administration (FDA) for diagnosis [3]. Each lab sets its own reference ranges, and there is no single universal range yet. This is why expert interpretation adds so much value.

Some practitioners use terms such as “mould toxicity” or chronic inflammatory response syndrome (CIRS). A urine mycotoxin test is not a diagnosis of either on its own. It is one of the tools a practitioner uses to build the picture.

What does the research say about mycotoxins and chronic illness?

A growing body of research links mycotoxins with several chronic conditions. These include ME/CFS, autism and neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Lab and animal studies also show that mycotoxins can affect the gut microbiome, the immune system and mitochondria, the energy centres of our cells.

Please note that much of this research is still at an early stage and there is no conclusive evidence on causation. Together, it supports mycotoxins as a possible contributing factor in chronic illness, and it is an active and expanding field. At Healthpath, we believe it is important to share and discuss the science as it evolves.

How strong is the evidence?

ME/CFS (chronic fatigue syndrome)

A 2013 study tested the urine of 112 people with ME/CFS. It found at least one mycotoxin in 93% of them, most often ochratoxin A (83%) [7]. In a subset of patients, environmental testing found mycotoxin-producing moulds in the water-damaged buildings they had been exposed to [7].

This study opened up an important line of research. It used an earlier antibody-based method (ELISA), and its comparison group was chosen for having no known mould exposure, which some researchers have questioned [8]. Larger studies using modern mass spectrometry would help build on it.

Autism

The largest study so far looked at 172 autistic children and 61 non-autistic children in Italy. It found significant differences in some mycotoxins between the groups, including deoxynivalenol in urine and ochratoxin A and aflatoxin M1 in blood [9]. It also found differences in immune markers. The authors called for a deeper look at the role mycotoxins may play [9].

A smaller pilot study of 54 children found no link between mycotoxins in urine and autism [10]. Most mycotoxins in that study were near the limit of detection. The authors suggested more sensitive testing and looking at exposure in pregnancy and early childhood [10]. This is an area where more research is clearly needed.

Parkinson’s, Alzheimer’s and brain health

Some of the most striking work comes from animal studies. In one study, mice given low oral doses of ochratoxin A for four weeks developed key features of Parkinson’s disease six months later. These included loss of dopamine nerve connections, movement problems and build-up of the protein alpha-synuclein in both the gut and the brain [11]. This fits with growing interest in the gut as a starting point for some brain conditions.

In people, a Spanish study measured mycotoxins in the blood of people with Parkinson’s, people with Alzheimer’s and healthy controls. Ochratoxin A was found in 89% of samples and sterigmatocystin in 88% [12]. Sterigmatocystin levels were significantly higher in patients than in controls. Ochratoxin A differences were more closely linked to sex than to disease [12].

Some clinicians also see a link between mould exposure and Alzheimer’s disease. In 2016, Dr Dale Bredesen described seven patients with a pattern of memory and thinking problems he called “inhalational Alzheimer’s disease” [13]. He linked it to breathing in toxins from moulds, such as those in water-damaged homes, and to chronic inflammatory response syndrome (CIRS). Symptoms in this pattern tend to start younger, often in the 40s to 60s, usually in people who do not carry the main genetic risk factor for Alzheimer’s (ApoE4). Moulds such as Stachybotrys, Penicillium and Aspergillus were found in some of the patients’ homes [13]. This idea comes from a small case series and has not yet been tested in larger studies. It has opened up an important new line of research.

A 2022 review described “growing evidence” linking mycotoxins with neurodegenerative diseases. It noted that firm conclusions still need more human research [14].

Gut microbiome

Mycotoxins and gut bacteria affect each other. In animal and lab studies, mycotoxins can change the balance of gut bacteria and weaken the gut lining [15]. Gut bacteria can in turn change mycotoxins, sometimes making them less harmful and sometimes more so [16]. There is more on this in the gut section below.

Immune system and autoimmunity

Mycotoxins can affect the immune system in several ways. Lab and animal studies show they can damage protective barriers in the gut and airways, lower the activity of some immune cells and drive inflammation [17]. Deoxynivalenol has been suggested as a possible risk factor for inflammatory bowel disease. In one mouse study, ochratoxin A sped up the progression of rheumatoid arthritis [17]. Research on autoimmunity in people is still at an early stage.

Mitochondria and energy

Mitochondria make most of the energy your cells use. Lab and animal studies show that some mycotoxins can disrupt them. A review of T-2 toxin, a trichothecene mycotoxin, found that it can damage the mitochondrial energy chain and raise oxidative stress in nerve cells [18]. This is one proposed reason why fatigue and brain fog are common complaints in people with mould exposure.

What does clinical practice add?

Research tells us what is possible. Clinical practice shows how it plays out in real people. In my experience as a functional medicine practitioner, mycotoxins can be a contributing factor in chronic illness, and in some people they are the main one. Many of the clients I see with stubborn gut symptoms have tried many approaches without lasting change. A number of them turn out to have spent time in a water-damaged building. This is clinical observation, not published research. It is why I think a positive result deserves careful attention, alongside your full history.

How should you interpret a positive mycotoxin result?

Think of a positive mycotoxin result as one clue. It becomes more meaningful when other clues point the same way. Examples include:

• living or working in a building with damp, leaks or a musty smell
• symptoms that ease when you are away from that building, such as on holiday
• levels well above the lab’s cut-off, rather than just detectable
• a pattern that includes markers more often linked to damp buildings than food, though this never proves the source

How do you read the numbers on a mycotoxin report?

Your report will usually list each marker, your result and the lab’s cut-off. Results are typically given per gram of creatinine, such as nanograms per gram (ng/g creatinine).

Keep three points in mind:

• Above the cut-off means detected. The cut-off is the lab’s reporting line, not a level linked to harm. How far above it you are helps your practitioner judge how significant the result is.
• Bands are set by each lab. They are not agreed health thresholds, so results from different labs cannot be compared directly.
• The pattern matters more than the label. How far above the cut-off you are, and which markers are raised, tell your practitioner more than the word “positive”.

Where could the mycotoxins be coming from?

There are two main routes: what you eat and what you breathe in. For most people, food is the more common source, but this low level exposure is of little concern. It is when we have been exposed to mould in a water damaged building that we are at risk of health issues.

Cereals are a common route. In the UK children’s study, higher cereal intake was linked to higher urine levels of several mycotoxins, and oat intake to T-2/HT-2 toxins [1]. Ochratoxin A is also found in coffee and grape products, and aflatoxins in nuts and maize [1].

Damp or water-damaged buildings can be another source. One study found mycotoxins in 45 of 62 building material samples from buildings with ongoing damp or past water damage. These included toxins made by Stachybotrys and Aspergillus moulds [19]. The World Health Organisation links indoor damp and mould with respiratory problems, although the exact role of mycotoxins is less clear [20].

Food vs building sources of mycotoxins: how to tell the difference

This table is a guide, not a rule. Some mycotoxins, including ochratoxin A, can come from both food and indoor moulds. Your practitioner will look at the whole pattern. It’s worth highlighting again that Healthpath recommend a low mould diet before completing the test to reduce the detection of mycotoxins from food.

What do the individual mycotoxins on your report mean?

Each marker points to a likely source. Deoxynivalenol and zearalenone usually point to food. Macrocyclic trichothecenes, gliotoxin and sterigmatocystin point more often to damp buildings. Ochratoxin A can come from either. Most of what we know about their effects comes from animal and lab studies at higher doses. So these notes describe what researchers study, not what a single result means for you.

If one food-related marker is mildly raised, diet is often the first thing to review. If several building-related markers are raised, your environment deserves a closer look.

What does a negative or borderline mycotoxin result mean?

A negative result means no mycotoxin was found above the lab’s cut-off at the time of testing. It does not rule out a damp home or past exposure, because urine mostly reflects recent exposure [1].

It also does not measure the main ways damp affects health. Most people come into contact with damp and mould by breathing in spores, allergens and irritants, which mainly affect the airways and lungs [25]. A urine mycotoxin test does not detect these.

Some mould-literate clinicians also believe a negative result can sometimes reflect poor detoxification rather than low exposure. Your liver changes mycotoxins into forms that are easier to remove, and many are then cleared through your kidneys into urine [1]. The idea is that if these pathways are not working well, mycotoxins may stay in the body instead of being cleared, so less shows up in your urine. This is a widely held clinical view, but it has not yet been tested in published research. In practice, it means a negative result should not rule out mould on its own if your symptoms and history strongly suggest it. Your practitioner can weigh your result against your full picture.

A borderline result, close to the cut-off, is best treated as uncertain. Your practitioner may suggest looking at your environment first, or retesting later with the same lab and preparation.

What should you do after a positive mycotoxin result?

Start with a practitioner review of your result alongside your symptoms and history. Then check your home and workplace for damp before changing your diet or starting any treatment. These steps work well in this order:

1. Talk it through with an experienced practitioner. They will read your result alongside your symptoms, diet and history. At Healthpath, a practitioner reviews your results alongside your intake questionnaire before any plan is made. [CONFIRM process wording.]
2. Look at your home and workplace. Check for leaks, condensation, musty smells and past flooding. UK government guidance says the underlying cause of damp must be tackled, because removing surface mould alone will not stop it coming back. It also names groups at greater risk, including children, older people, pregnant women and people with asthma or weakened immune systems [25].
3. Consider a professional survey if you suspect hidden damp. A musty smell without visible mould can mean mould is growing behind wallpaper, panelling or carpets, or inside ventilation units. A qualified damp surveyor can identify the cause [25].
4. Review your diet. Store grains, nuts and dried fruit in cool, dry conditions. Throw away food with visible mould. Eat a varied diet so no single food dominates.
5. Look after your general health. Sleep, regular movement, enough water and plenty of plant foods are good foundations while you investigate.
6. Avoid starting strong treatments on your own. Binders and antifungal medicines are not suitable for everyone. Some binders reduce the absorption of other medicines. For example, other medicines should be taken at least 1 hour before or 4 to 6 hours after the prescription binder colestyramine [26]. Only use them with professional guidance.
7. Retest after changes, if your practitioner advises it. Use the same lab and the same preparation, so results can be compared fairly.

What if you rent your home?

If you rent and suspect damp, report it to your landlord in writing and keep photos. In England, both private and social landlords have legal duties on damp and mould, including under the Housing Act 2004 and the Homes (Fitness for Human Habitation) Act 2018. Your local council can also inspect the property [25].

How does your gut fit in after a positive mycotoxin result?

Your gut is the first place most mycotoxins meet your body, because most exposure comes through food. That makes gut health a sensible part of the picture.

In animal and lab studies, several mycotoxins can weaken the gut lining and change the balance of gut bacteria [15]. Gut bacteria also interact with mycotoxins. Lab work shows they can release the original toxins from “masked” forms found in cereals, so these masked forms can add to your total exposure [27]. Human evidence is still limited, so treat these links as plausible rather than proven.

If you have ongoing gut symptoms alongside a positive result, gut testing can show what is happening in your digestive system. Neither test below detects mould or mycotoxins. They look at your gut directly.

• The Ultimate Gut Heath Test is a comprehensive stool test. It looks at your gut bacteria, digestion, inflammation and gut barrier markers, then gives you a practitioner-led plan.
• The SIBO Test is a breath test for small intestinal bacterial overgrowth. It may help if bloating, wind or changes in bowel habit are your main symptoms.

A note on fibre and IBS

Plant foods and fibre support a healthy gut for most people. If you have IBS, some high-fibre foods can worsen bloating or pain. NICE advises that a low-FODMAP diet should be guided by a healthcare professional with expertise in dietary management [28].

When should you see your GP?

A mycotoxin result should never delay medical care. See your GP if you have any of these:

• blood in your poo, which may look red or black, or bleeding from your bottom
• a change in your bowel habit that is not usual for you
• losing weight without trying
• tummy pain or a lump in your tummy [29]
• breathlessness that gets worse during normal activities or when you lie down
• a cough that has lasted 3 weeks or more [30]

Ask for an urgent GP appointment or contact NHS 111 if your poo is black or dark red, or you have bloody diarrhoea [29]. Call 999 if you have severe difficulty breathing [30]. These symptoms need checking in their own right, whatever your test shows.

Can you take a mycotoxin test if you are pregnant or breastfeeding?

Healthpath does not currently recommend urine mycotoxin testing during pregnancy or breastfeeding. The test has too many limits to guide decisions safely during this time. If you are worried about damp at home, your GP and midwife can support you. Tackling the damp itself is still worthwhile, as UK guidance lists pregnant women among those at greater risk from damp and mould [25].

Frequently asked questions

Is a positive mycotoxin result serious?

Not necessarily. Most people have detectable mycotoxins in their urine, both children [1] and adults [2]. What matters is how high the levels are, which markers are raised and whether your symptoms and environment fit the picture.

Does a positive mycotoxin result mean I have mould illness?

Not on its own. It shows exposure, and levels that predict disease have not yet been established [3]. Read alongside your symptoms and history, it can help your practitioner judge whether mycotoxins are likely to be contributing to how you feel.

Can a positive result come from food alone?

Yes. Diet is the main source of mycotoxins for most people. Cereals, oats, coffee, grape products and nuts are common sources [1]. A low-mould diet before testing helps reduce this effect.

Does a positive result prove I have mould in my home?

No. A urine test shows exposure but not where it came from. The pattern of markers can offer clues, and an inspection of your home or workplace is the way to find out.

Why is my ochratoxin A still high after I changed my diet?

Ochratoxin A can stay in the body for weeks, with an estimated half-life of around 35 days [5]. Levels may take time to fall. An ongoing source, such as a damp building, is also worth ruling out.

Should I retest?

Retesting can be useful after you have made changes to your diet or environment. Your practitioner can advise on timing. Use the same lab and preparation so the results are comparable.

Can I treat mycotoxins myself?

We advise against starting binders, antifungals or detox protocols without professional support. They are not right for everyone, and some binders can reduce the absorption of other medicines [26]. An experienced practitioner can build a plan that suits you.

Can I take a mycotoxin test if I am pregnant or breastfeeding?

Healthpath does not currently recommend it. The test’s limits make it unsuitable for guiding decisions during this time. Your GP and midwife can help if you are worried about damp at home.

Related reading

• Who Should and Shouldn’t Take A Mycotoxin Test?
• 7 Signs You Could Be Experiencing Mould Exposure
• 9 Hidden Places You’re Exposed To Mould Every Day
• Can Mould Toxicity Cause SIBO?
• Could My Gut Issues Be Coming From Mould

Scientific references

1. Charusalaipong P, Gordon MJ, Cantlay L, De Souza N, Horgan GW, Bates R, Gratz SW. Frequent dietary multi-mycotoxin exposure in UK children and its association with dietary intake. Toxins. 2024;16(6):251.
2. Turner PC, Rothwell JA, White KLM, Gong Y, Cade JE, Wild CP. Urinary deoxynivalenol is correlated with cereal intake in individuals from the United Kingdom. Environ Health Perspect. 2008;116(1):21–25.
3. Centers for Disease Control and Prevention. Notes from the field: use of unvalidated urine mycotoxin tests for the clinical diagnosis of illness — United States, 2014. MMWR. 2015;64(6):157–158.
4. Dasí-Navarro N, Lozano M, Llop S, et al. Development and validation of LC-Q-TOF-MS methodology to determine mycotoxin biomarkers in human urine. Toxins. 2022;14(10):651.
5. Studer-Rohr I, Schlatter J, Dietrich DR. Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans. Arch Toxicol. 2000;74(9):499–510.
6. De Santis B, Debegnach F, Toscano P, Crisci A, Battilani P, Brera C. Overall exposure of European adult population to mycotoxins by statistically modelled biomonitoring data. Toxins. 2021;13(10):695.
7. Brewer JH, Thrasher JD, Straus DC, Madison RA, Hooper D. Detection of mycotoxins in patients with chronic fatigue syndrome. Toxins. 2013;5(4):605–617.
8. Osterman JW. Comment on Detection of Mycotoxins in Patients with Chronic Fatigue Syndrome. Toxins. 2016;8(11):322.
9. De Santis B, Raggi ME, Moretti G, et al. Study on the association among mycotoxins and other variables in children with autism. Toxins. 2017;9(7):203.
10. Duringer J, Fombonne E, Craig M. No association between mycotoxin exposure and autism: a pilot case-control study in school-aged children. Toxins. 2016;8(7):224.
11. Izco M, Vettorazzi A, de Toro M, et al. Oral subchronic exposure to the mycotoxin ochratoxin A induces key pathological features of Parkinson’s disease in mice six months after the end of the treatment. Food Chem Toxicol. 2021;152:112164.
12. Arce-López B, Alvarez-Erviti L, De Santis B, et al. Biomonitoring of mycotoxins in plasma of patients with Alzheimer’s and Parkinson’s disease. Toxins. 2021;13(7):477.
13. Bredesen DE. Inhalational Alzheimer’s disease: an unrecognized—and treatable—epidemic. Aging (Albany NY). 2016;8(2):304–313.
14. Nguyen VTT, Koenig S, Eggert S, Endres K, Kins S. The role of mycotoxins in neurodegenerative diseases: current state of the art and future perspectives of research. Biol Chem. 2022;403(1):3–26.
15. Liew WPP, Mohd-Redzwan S. Mycotoxin: its impact on gut health and microbiota. Front Cell Infect Microbiol. 2018;8:60.
16. Guerre P. Mycotoxin and gut microbiota interactions. Toxins. 2020;12(12):769.
17. Brown R, Priest E, Naglik JR, Richardson JP. Fungal toxins and host immune responses. Front Microbiol. 2021;12:643639.
18. Dai C, Xiao X, Sun F, et al. T-2 toxin neurotoxicity: role of oxidative stress and mitochondrial dysfunction. Arch Toxicol. 2019;93(11):3041–3056.
19. Bloom E, Bal K, Nyman E, Must A, Larsson L. Mass spectrometry-based strategy for direct detection and quantification of some mycotoxins produced by Stachybotrys and Aspergillus spp. in indoor environments. Appl Environ Microbiol. 2007;73(13):4211–4217.
20. World Health Organization. WHO guidelines for indoor air quality: dampness and mould. Copenhagen: WHO Regional Office for Europe; 2009.
21. International Agency for Research on Cancer. Some naturally occurring substances: food items and constituents, heterocyclic aromatic amines and mycotoxins. IARC Monographs Volume 56. Lyon: IARC; 1993.
22. Food Standards Agency. Survey on sterigmatocystin in food. FSA research project.
23. EFSA Panel on Contaminants in the Food Chain. Scientific opinion on the risk for public and animal health related to the presence of sterigmatocystin in food and feed. EFSA Journal. 2013;11(6):3254.
24. Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment. Statement on the potential risk from citrinin in the maternal diet. COT; 2025.
25. Ministry of Housing, Communities and Local Government, Department of Health and Social Care and UK Health Security Agency. Understanding and addressing the health risks of damp and mould in the home. GOV.UK; 2023, updated 1 April 2026.
26. Electronic Medicines Compendium. Colestyramine 4 g Powder for Oral Suspension: summary of product characteristics. emc.
27. Gratz SW, Dinesh R, Yoshinari T, et al. Masked trichothecene and zearalenone mycotoxins withstand digestion and absorption in the upper GI tract but are efficiently hydrolyzed by human gut microbiota in vitro. Mol Nutr Food Res. 2017;61(4):1600680.
28. National Institute for Health and Care Excellence. Irritable bowel syndrome in adults: diagnosis and management (CG61). NICE; 2008, updated 2017.
29. NHS. Symptoms of bowel cancer. NHS website; reviewed September 2026.
30. NHS. Shortness of breath. NHS website.

This article is for educational purposes only. It is not intended to diagnose, treat, cure or prevent any disease. Always speak to your GP or a qualified healthcare professional about your health.