Who Should and Shouldn’t Take A Mycotoxin Test

If you have had gut symptoms, fatigue or brain fog for months or years, you may have wondered about mould. Perhaps you have lived in a damp flat, or you feel better on holiday? So who should or shouldn’t take a mycotoxin test?

In short, a urine mycotoxin test is most useful if you have long-standing symptoms and a history of damp or water-damaged buildings. It helps least if you have no symptoms and no history of damp or mould, or you have red-flag symptoms your GP hasn’t checked.

Key takeaways

• A urine mycotoxin test measures levels of mould toxins your body is clearing. It shows exposure, not illness.
• It is most useful if you have long-standing symptoms, a history of damp or water-damaged buildings, and the common medical causes have already been checked.
• It is less useful if you have no symptoms and no exposure history, or if you have new red-flag symptoms that need your GP first.
• Speak to us first if you are thinking of testing but have kidney problems, are pregnant or considering testing a child.
• Most people carry some mycotoxins from food. In one UK study, a cereal toxin was found in 98.7% of adults’ urine [8]. That’s why results need practitioner-led interpretation.
• A urine test can’t tell you where a toxin came from. A professional damp or mould survey is the best way to check a building.

This guide explains what a mycotoxin test measures, who it helps most, who should wait or talk to us first, and what a result can and cannot tell you. It draws on test information from Healthpath’s laboratory partner, and on guidance from public health bodies.

What does a mycotoxin test actually measure?

A urine mycotoxin test measures levels of mould toxins, and their breakdown products, that your body is clearing in your urine. It tells you that your body has encountered a toxin. It doesn’t tell you how much you were exposed to, when, or where it came from.

Mycotoxins are toxic compounds made by some moulds. They reach us through food and through the air in damp or water-damaged buildings.

The testing process looks for mould toxins in one urine sample, using a very sensitive method called LC-MS/MS that picks up tiny amounts. Urine can be weaker or stronger depending on how much water you’ve had. So the lab adjusts your result using a marker called creatinine.

The main groups measured include:

Each result is shown against a laboratory cut-off. A raised marker tells you your body is clearing that toxin.

Who should take a mycotoxin test?

You are most likely to benefit if you:

• have lived or worked in a damp or water-damaged building
• have long-standing symptoms that haven’t settled
• feel better away from a particular building
• or have gut symptoms that keep coming back despite good care

A test works best when it answers a clear question, as one part of a wider assessment alongside your history and symptoms.

1. You have lived or worked in a damp or water-damaged building

This might be a past leak, a flood, rising damp or long-term condensation. The World Health Organisation links damp and mouldy buildings with more respiratory symptoms, allergies and asthma, and with effects on the immune system [1]. UK government guidance also notes that damp alone can raise health risks, even when you can’t see mould [2]. To see what other symptoms research has linked to mould exposure, read our guide to the 7 signs you could be experiencing mould exposure.

2. Your symptoms have lasted a long time and haven’t settled

Brain fog, chronic fatigue, low mood, digestive issues, headaches, sinus congestion and skin rashes are among the common reasons practitioners request this test. All of these have many possible causes. A test helps most once the common causes have been checked and you know or suspect you’ve been in a water-damaged building. Bear in mind that mould can sit in wall cavities, behind wallpaper and under floorboards. You can’t see it there, so it’s hard to rule out.

3. You feel better away from a particular building

Some people feel clearer on holiday or when working somewhere else. That pattern doesn’t prove mould is involved, as your stress levels, routine and diet can change when you’re away too. It is still a useful clue.

4. Your gut symptoms keep coming back despite good care

In my clinical practice, I have seen many people with stubborn bloating or recurring SIBO who had tried diet changes, supplements and stress work without lasting change. A number of them had lived or worked in water-damaged buildings. You may like to check out our article exploring whether mould toxicity can cause SIBO. This is a clinical observation, not research. It is one reason I always consider mould exposure in chronic cases.

5. You and your practitioner want a baseline

Some practitioners test before and after a home has been repaired, to see how results change. If you do this, use the same laboratory each time. Different labs use different methods and cut-offs, so results from two labs can’t be compared fairly.

Who shouldn’t take a mycotoxin test, or should wait?

You should see your GP first if you have unchecked red-flag symptoms or are acutely unwell. Testing may not help yet if you have no symptoms or exposure history, mainly want to prove a building is the cause, or aren’t ready to act on a result. Kidney problems, pregnancy and testing a child don’t rule testing out, but please speak to us first.

Wait: see your GP first

You have new or worrying symptoms that haven’t been checked. Unexplained weight loss, bleeding from the bottom, anaemia, or a lasting change in your bowel habits all need your GP first, whatever your age. NICE guidance says these “red flag” signs should be assessed before gut symptoms are put down to a functional cause such as irritable bowel syndrome (IBS) [3]. NICE also advises testing for coeliac disease in people with IBS-type symptoms [3]. A mycotoxin test should never delay these checks.

You are unwell right now with a cold, flu or infection. We recommend you recover fully before collecting any sample, as illness may affect results.

Talk to us first

You have kidney disease or reduced kidney function. Results are adjusted using creatinine, a waste product your kidneys clear. Creatinine levels vary with age, sex, body size and muscle mass [4], and kidney function itself can change how much of a substance, and how much creatinine, appears in your urine [5]. Ochratoxin A is also toxic to the kidneys and clears slowly, with a blood half-life of around 35 days in humans [6]. None of this means you can’t test. It means your practitioner needs to know about your kidney health so your result is read in the right context.

You want to test a child. Children have lower urinary creatinine than adults, which affects how adjusted results are read [4]. Any plan should involve your child’s GP.

Testing may not help yet

You have no symptoms and no exposure history. Low levels of mycotoxins are found in many foods, so they turn up in the urine of healthy people too [7]. A UK study found deoxynivalenol, a toxin linked to cereals, in 296 of 300 adults’ urine samples (98.7%) [8]. A Belgian study found ochratoxin A in 51% of children’s and 35% of adults’ samples, and a deoxynivalenol marker in every sample tested [9]. Testing out of curiosity alone can cause worry about results that may simply reflect a normal diet.

You mainly want to prove a building is making you ill. A urine result can’t show where a toxin came from, or confirm that a specific home or workplace is the cause. US military health guidance states that, outside rare acute poisonings, urine mycotoxin results reflect toxins taken in through food rather than breathed in [10]. If you suspect a problem building, a professional damp or mould survey is the right first step. UK guidance stresses fixing the cause of damp, not just removing visible mould [2].

You are pregnant or breastfeeding. We’d suggest waiting. The plan that follows a result often includes steps that aren’t suitable for , including diet changes or supplements. Our FAQ explains more.

You aren’t ready to act on the result. A result is most useful when you can do something with it, such as reviewing your home or your diet. If now isn’t the right time, it’s fine to wait.

How reliable is a urine mycotoxin test?

A urine mycotoxin test reliably measures exposure, but no levels have been set that predict illness. That means it can show what your body is clearing, but it can’t diagnose a condition on its own. There are two sides to the evidence, and it’s worth knowing both.

What a urine mycotoxin test can show:

• Which mycotoxins your body is clearing right now.
• A baseline to compare against over time.
• Exposure at the individual level, using sensitive lab method.

What it can’t show:

• Whether those toxins are causing your symptoms.
• Where the toxins came from. Because mycotoxins are frequently found in food results could be simply showing dietary exposure. This is why at Healthpath we recommend following a low mould diet for at least 3 days before doing the test.
• A diagnosis of “mould illness” or any other condition.

The supportive view

Researchers have used urine tests to measure mycotoxin exposure for many years. A 2026 review of 25 years of studies shows how sensitive lab methods can now pick up these toxins in human urine[11]. UK research for the Food Standards Agency found that a urine marker was sensitive enough to measure one person’s exposure [12]. So the test can measure exposure. What a given level means for your health is still an open question

The cautious view

Public health bodies are clear about what a urine result can’t do. It isn’t approved for diagnosing illness. The US Centers for Disease Control and Prevention (CDC) says no mycotoxin levels have been shown to predict disease [7]. US military health guidance adds that there are no reference ranges for healthy people. It also says that, apart from rare cases of acute poisoning, results reflect food rather than mould in the air [10]. That’s why a result is only one part of the picture.

Why we pair every result with a practitioner review

A mycotoxin test can show what your body is clearing, but it can’t diagnose a condition on its own. Some practitioners in functional and environmental medicine use the terms “mould illness” or CIRS (chronic inflammatory response syndrome) for a cluster of symptoms linked to damp buildings. These aren’t mainstream diagnostic labels, and a urine result can’t confirm them. That’s why Healthpath always pairs a result with a full history and practitioner review. Tiredness, brain fog and gut symptoms can all have many causes that overlap, so it takes expert insight to see how your result fits in and to plan a clear next step

What about mould and chronic fatigue?

A 2013 study found mycotoxins in the urine of 93% of 112 people with chronic fatigue syndrome [13]. People often quote this finding. Other researchers have criticised the study, because its healthy comparison group had no history of damp buildings. That may have made the difference look bigger than it was [14]. The study also used a different type of test from the one in our panel. This type is an antibody-based method called ELISA. It raises a question worth exploring, but it doesn’t give a firm answer.

How should you prepare for a mycotoxin test?

Prepare by following a low-mould diet for about three days, stopping all necessary supplements (as laid out in our instructions), waiting until you’re well, completing your symptom questionnaire, and then collecting a single urine sample at home. Good preparation makes your result easier to interpret.

1. Follow a low-mould diet for about three days. Grains, nuts, spices, coffee and dried fruit can all carry mycotoxins [15]. Healthpath recommends reducing these before testing. This is our protocol rather than an established standard, but it aims to reduce the background from recent meals so your result is easier to read. We will send you guidance on what to eat.
2. Check your supplements and medicines. Never stop a prescribed medicine without speaking to your GP.
3. Wait until you are well. Collect your sample once you have fully recovered from any recent illness.
4. Complete your symptom questionnaire. This tells your practitioner about your home, work and health history, so your result is read in context.
5. Collect and return your sample. The test needs a single urine sample, collected at home with the kit provided.

What happens after your mycotoxin test results come back?

One of Healthpath’s practitioners reviews your results alongside your symptoms and history. You then receive a personal health plan covering food, lifestyle and supplements, plus a recorded video explaining your results.

If you’re ready to take the next step, join our Mycotoxin Waitlist to be first to hear when the test is live.

What if gut symptoms are your main concern?

A mycotoxin test doesn’t look at your gut. If digestion is your biggest problem, check the common causes first. Bloating, wind and changeable bowel habits are often linked to IBS, and fermentable carbohydrates (FODMAPs) in everyday foods can trigger the same symptoms. NICE guidance recognises dietary changes, including a low-FODMAP approach under the guidance of a professional with dietary expertise, as part of managing IBS [3].

Healthpath’s Ultimate Gut Plan looks at your gut microbiome alongside markers of digestion and gut health. If bloating soon after eating is a key symptom, the SIBO Test uses a breath test to look for small intestinal bacterial overgrowth. Neither test detects mould. Your practitioner can help you decide which test, or combination, fits your situation.

If you’d like to read more on mould and your health, see 7 Signs You Could Be Experiencing Mould Exposure, 9 Hidden Places You’re Exposed To Mould Every Day and Can Mould Toxicity Cause SIBO?.

Frequently asked questions

Can a mycotoxin test tell me if I have mould in my home?

No. A urine test shows toxins your body is clearing, from food or the air. It can’t tell you where they came from [10]. A professional damp or mould survey is the way to check a building.

Is it normal to have mycotoxins in my urine?

Yes, low levels are common. A UK study found a cereal-linked mycotoxin in 98.7% of adults’ urine samples [8], and a Belgian study found widespread exposure in both adults and children, largely from food [9]. This is why results need careful interpretation.

Does a high result mean mould is causing my symptoms?

Not on its own. A raised result shows exposure, not cause, and levels that predict disease haven’t been established [7]. Your practitioner will consider it alongside your history, symptoms and other test results.

Why do I need to change my diet before testing?

Many everyday foods, including grains, nuts, coffee and dried fruit, carry small amounts of mycotoxins [15]. Healthpath recommends a low-mould diet for about three days to reduce this background, so your result is easier to read.

Can I take a mycotoxin test if I have kidney problems?

Yes, but please speak to us first. Results are adjusted using creatinine, and kidney function can affect how much creatinine and toxin appear in your urine [5]. Your practitioner needs to know about your kidney health to read your result in context.

Can I test my child?

Please speak to the Healthpath team first. Children have lower urinary creatinine than adults, which affects how adjusted results are read [4]. Any plan should involve your child’s GP.

How long do mycotoxins stay in the body?

It varies by toxin. Many clear within hours to days, but some are held for weeks. Ochratoxin A, for example, has a blood half-life of around 35 days in humans [6].

Should I retest later?

Some practitioners retest after a building has been repaired, to see how results change. Your practitioner can advise whether this would be useful for you, and when.

Can I take a mycotoxin test while pregnant or breastfeeding?

We understand why you might want to. If you are worried about damp or mould at home, it is natural to want answers, especially when you are caring for a baby. However, we don’t recommend a urine mycotoxin test during pregnancy or while breastfeeding.

This is because a result is only helpful if you can act on it. Most of the steps we would usually suggest after a test, such as binders or detox-support supplements, aren’t suitable at this time. A result could leave you with worry and no clear way forward, and we don’t want that for you.

There is still a lot you can do. The most helpful step is reducing exposure in your home. That means tackling the cause of any damp, keeping rooms ventilated, and having mould removed safely by someone else (GOV.UK, 2023) [4]. Please share any concerns or symptoms with your midwife or GP. When you have finished breastfeeding, we would be glad to talk through whether testing makes sense for you.

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 symptoms.

Scientific references

1. World Health Organization. WHO Guidelines for Indoor Air Quality: Dampness and Mould. Copenhagen: WHO Regional Office for Europe; 2009.
2. Department of Health and Social Care & UK Health Security Agency. Understanding and addressing the health risks of damp and mould in the home. GOV.UK; 2023.
3. National Institute for Health and Care Excellence. Irritable bowel syndrome in adults: diagnosis and management (CG61). 2008, updated 2017.
4. Barr DB, Wilder LC, Caudill SP, Gonzalez AJ, Needham LL, Pirkle JL. Urinary creatinine concentrations in the U.S. population: implications for urinary biologic monitoring measurements. Environ Health Perspect. 2005;113(2):192–200.
5. Weaver VM, Kotchmar DJ, Fadrowski JJ, Silbergeld EK. Challenges for environmental epidemiology research: are biomarker concentrations altered by kidney function or urine concentration adjustment? J Expo Sci Environ Epidemiol. 2016;26(1):1–8.
6. Petzinger E, Ziegler K. Ochratoxin A from a toxicological perspective. J Vet Pharmacol Ther. 2000;23(2):91–98.
7. Kawamoto M, Page E. Notes from the field: use of unvalidated urine mycotoxin tests for the clinical diagnosis of illness — United States, 2014. MMWR Morb Mortal Wkly Rep. 2015;64(6):157–158.
8. 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.
9. Heyndrickx E, Sioen I, Huybrechts B, Callebaut A, De Henauw S, De Saeger S. Human biomonitoring of multiple mycotoxins in the Belgian population: results of the BIOMYCO study. Environ Int. 2015;84:82–89.
10. Navy and Marine Corps Force Health Protection Command. Urine mycotoxin testing. November 2024.
11. Mîrza O, Pașca D, Manyes L, Cozma-Petruț A, Banc R, Hegheș SC, Filip L, Kiss B. Twenty-five years of human urinary biomonitoring of mycotoxins: analytical advances and applications in risk assessment. Toxins. 2026;18(9):390.
12. Turner PC, Cade JE, Wild CP (University of Leeds), for the Food Standards Agency. Urine as a biomarker of exposure to Fusarium mycotoxins. Project report C03044.
13. 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.
14. Osterman JW. Comment on Detection of Mycotoxins in Patients with Chronic Fatigue Syndrome. Toxins 2013, 5, 605–617. Toxins. 2016;8(11):322.
15. Food Standards Agency. Mycotoxins. Business guidance.