mold spores

Top 7 Home Mold Testing Mistakes – What to know when you have Mast Cell Activation Syndrome or Mold Toxicity

Hindsight is 20/20.  
Looking back, I can clearly see the points in time where my health took major hits. And they usually happened right alongside a move to a new home or office space.  

These places all had one thing in common…Toxic Mold. 

The first place I lived with toxic mold was my childhood home. My parents bought a 100-year-old country farmhouse to fix up.  

For a 7-year-old, it was a big adventure!  

But my health went downhill just a few years after we moved in. By the time I was 9, I was getting hives head to toe. 

While I was sleeping, I would scratch my skin so hard, I’d wake up with blood stains on my arms, legs, and sheets. 

Many years later we learned toxic mold completely lined the crawl space under the house. 

This wasn’t the only time I got exposed to mold through. It kept happening for another 20 years! 

This is why I got so sick.

When I went to college, I lived in a 150-year-old duplex.  

There was always a musty smell in the basement. And when it rained hard, the basement would end up with a stream of water going through it. 

I moved into a little cottage years later. It was so cute and sat on 5 beautiful acres of woods. 

But I eventually found out there was mold behind the shower wall.   

Then there was the office I rented on the lower level of a magnificent historic building.  

I never thought anything about the fact that the basement had previously flooded. Or that the exposed brick was crumbling from water damage. Or the plaster walls felt damp. 

When I left that space, I realized all my belongings were contaminated. I had to remediate what I could and throw away everything from the office that the mold toxins and seeped into. 

Looking back, I can track each of my major health declines with each new exposure to toxic mold.

woman holding head

Using hindsight, you might find some of your health problems can be tracked to places you’ve lived, worked, or gone to school, too.  

I didn’t always know the effects toxic mold can have on health. Once I learned, though, I saw how important it was to test home, workplaces, and even schools for mold.   

The best way to know if mold is majorly affecting your health is test for it.  

Many people feel really overwhelmed just thinking about it, though. And they are afraid they’ll have to move or throw everything out. 

But that’s not the case. Most people don’t have to move.  

And while some belongings may need to be remediated, you don’t necessarily have to throw everything away, either (unless you’re the most sensitive of the sensitive people). 

I get a lot of questions about environmental mold testing: 

  • Can you test for mold in your home, workplace, or school? 
  • How do you test for mold? 
  • What are the best ways to test for mold? 
  • Is an air test enough? 
  • Is a little mold in my home ok? 

And after meeting with client after client struggling with mold toxicity, I’ve learned there are a lot of testing mistakes happening. 

These mistakes can cost time and money. Which is why I want to share this with you, to help you avoid these costly mistakes. 

First, let’s start by looking at how mold grows. 

How Mold Grows and Became Epidemic – What to know if you have Mast Cell Activation Syndrome or Histamine Intolerance

Mold Growth in petri dish

To get mold growth you just need 3 things:  

  1. Mold spores (They are everywhere and impossible to avoid.) 
  2. Moisture (Water either from humidity, flooding, or even tiny leaks in pipes.) 
  3. A food source (Drywall, carpets, caulking, wallpaper, dust, paints, glues, etc.) 

If these 3 things are present, you can easily get mold growth. And that’s true whether it’s a new or older building. 

Most homes have a lot of materials mold can grow on. And it just takes humidity above 50% for over 24-48 hours to provide enough moisture for mold to thrive. 

An EPA study found about 47% of homes have mold.   

So, you’ve seen why it’s so important to test your home for mold.  

Now, let’s cover the most common types of home mold testing and pros/cons. 

Then, we’ll cover the Top 7 Home Mold Testing Mistakes. 

Most Common Types of Environmental Mold Testing

Aspergillus mold spores

Molds are challenging to test for. A mold testing method might miss the mold in one home and find it in another.   

There is no one perfect mold test. So, it is best to use multiple methods. 

Let’s look at a few of the most popular methods.  

Air Testing refers to tests that collect and test air samples. These samples are then looked at under a microscope to see if mold is present.  

These tests can detect both live and dead mold spores. Companies that conduct this type of testing may also compare samples between inside and outside the building.   

The problem is that mold spores are heavy and fall to the ground. Very few spores are floating in the air.  

This means the Air Testing method often only catches the worst of mold issues, because all the mold spores on the floor won’t show up in the sample tested.   

It also can’t detect mold issues behind a wall. 

I’ve seen hundreds of mold inspection reports from my clients. If Air Testing is the only method used, it very frequently missed the levels of mold that can make sensitive people sick. 

ERMI (Environmental Relative Moldiness Index) uses a mold-specific DNA test to detect the presence and levels of mold in dust samples.  

The dust samples may be from carpet dust or other gathered dust. It is a very sensitive test that can find both live and dead mold spores. 

But, it might miss mold that is behind a wall. 

Mold Plate Testing directly tests for live mold spores. To do this, you place petri dishes in areas you’re testing. If live mold spores are present, they will fall onto the plates. If mold spores are present, the plates will grow mold.  

You can send these mold plates to the lab to identify species of mold that grow.  

This still won’t catch issues behind a wall, either. For that, a really good mold inspector is needed who will check behind walls, do a thorough visual inspection, and use multiple testing methods. 

However, even when all three of these tests come back negative, you can still have mold problems.  

Mold can release mold toxins as gas into the air. But they may not be releasing enough spores for these tests to detect.  

I recommend combining the ERMI and mold plates for environmental testing you can do yourself.

I also recommend using humidity gauges in each room of the house to make sure the humidity stays under 50%. Here’s the brand I’m using that has been very accurate:

Then, if you still have concerns, I also recommend adding these other approaches: 

  • Visual inspection by a professional inspector who gets the health issues sensitive people experience (tip: there aren’t many inspectors who understand this) 
  • Volatile organic compound meter  
  • Infrared camera to identify damp areas 

So now you know a little bit about the types of tests. Next, let’s look at some of the common mold testing mistakes I see. 

Top 7 Mold Testing Mistakes – What to know when you have Mast Cell Activation Syndrome or Histamine Intolerance


1. Thinking that a little mold can’t hurt  

Toxic molds refer to species that produce mycotoxins. Mycotoxins can make people very sick.  

Toxic molds include: 

  • Alternaria 
  • Aspergillus 
  • Chaetomium 
  • Fusarium 
  • Mucor 
  • Penicillium 
  • Stachybotrys 
  • Wallemia 

There are also many other types of mold that grow in dirt. These are molds like Cladosporium or Microsporium. They don’t make mold toxins. 

If you don’t have a mold allergy, a little non-toxic mold exposure is usually okay.  

But if you have mold allergy, the spores from the non-toxic molds can still irritate the airway and cause allergy symptoms.  

But remember, if you have non-toxic molds growing in your home, then you also have the environment that can grow toxic mold. 

2. Thinking there can’t be any mold because you can’t see or smell it 

When I moved into my moldy office in a historic building, I couldn’t smell the mold. 

But that office made me sicker than I already was. 

Many people can’t smell mold unless they have a very sensitive sense of smell. In fact, being around mold toxins can reduce your sense of smell to the point you can’t smell it anymore. 

This is why it can be very important to do thorough mold inspection and testing.  

Also, because mold tends to hide in wet, damp, and dark areas, they tend to be invisible.  

Mold tends to be underneath wallpaper or in the drywall where you can’t see it. 

And mold can hide in: 

  • Furniture 
  • Pets 
  • Cars 
  • Attics, roofs, insulation materials, and crawl space  
  • Appliances, especially air conditioners, dishwashers, and front loader washing machines.  

3. Forgetting to check other places you spend time  

Remember that other places you visit like school, church, and the gym could also be moldy.  

Schools, dorms, and churches tend to close for extended periods of time. During this time, they turn off their AC. This allows the humidity to rise.  

Once the humidity goes above 50%, mold can start growing.  

If you can, it’s very important to check these types of areas and get them inspected.   

Missing these areas means you may continue to be exposed to mold on a regular basis.  

I’ve had clients who got their homes remediated but were still struggling. They later realized they were getting exposed every time they went to their parents’ home. 

Also, for children, think about schools. For college students, think about dorms. 

4. Only using 1 testing method 

You learned before, there is no perfect environmental mold test.  

The all have their pros and cons.  

Which is why I recommend using both mold plates and ERMI.   

But even then, if they all come back negative and there are still suspicions, you may need to hire a skilled mold inspector to do a thorough check.  

5. Thinking that a negative finding means everything is okay 

A negative environmental mold test result doesn’t mean everything is okay. Especially if you’re still feeling awful. 

Mold can grow behind walls, where it stays concealed. 

But their toxins can still seep into the air. These toxins aren’t detectable by air testing, ERMI, or mold plates.  

That’s why I always recommend sending mold plates with any growth to a lab to identify which species you have.  

However, if air testing, ERMI, or mold plates all come back negative, you can still have mold problems.  

6. Using just any mold inspector  

The mold inspection and remediation industry are a wild, wild west. Even though over 50% of buildings have mold nowadays, there is little regulation around mold inspection or remediation.    

Also, no official standards exist for determining if a building has mold, or whether a level of mold is acceptable.  

Mold inspector certification training is actually very minimal.   

Mold inspectors have to do a lot of additional education to understand what people with sensitivities and Mast Cell Activation Syndrome face from mold and how to be that thorough. 

I’ve had multiple clients spend close to $6,000 on 3 different mold inspectors because they knew there was mold in their homes.  

For some of these clients, all 3 mold inspectors told them there was no mold.  

I encouraged them to run mold plates and an ERMI themselves to be certain. For most of these clients who were so sick from mold, these tests showed clear toxic mold. 

And unfortunately, many mold inspectors don’t account for checking for levels that can make the very sensitive population sick.   

Just make sure the inspector has a reputation for working with sensitive people who are bothered by lower amounts of mold.  

You can ask the inspector what they understand about Mold Toxicity and really sensitive people. If they attend conferences on the health effects of mold, that can be a good sign. 

If you have Mast Cell Activation Syndrome and you’re going to do mold plate testing at home, here is my tip on reading the results for yourself so you can double check. 

My Key for Reading Mold Plates for Sensitive People with Mast Cell Activation Syndrome

a key

I recommend more stringent cutoffs on the mold plates for people dealing with Mast Cell Activation Syndrome. 

Here is the key I use: 

A count of 1 or more circles of the following species indicates a toxic mold problem:  

  • Mucor 
  • Stachybotrys (rarely shows on mold plates) 

A count of 2 or more circles of the following indicates a toxic mold problem: 

  • Aspergillus 
  • Fusarium 
  • Penicillium 
  • Alternaria 

Also, 1 count of a combo of any of these on a mold plate, such as 1 Aspergillus + 1 Penicillium, indicate a toxic mold problem. 

But sometimes, you really do need an inspector. If something is really hidden behind a wall, it may not show on a mold plate or ERMI.

So, what do you look for in a mold inspector? Here are a few things to consider:  

A good mold inspector should be: 

  • Checking under carpets 
  • Using a moisture meter to check for problems behind walls 
  • Running a variety of testing methods 
  • Checking your HVAC and ductwork 
  • Ethical and transparent in how they operate 
  • Asking about your health and take into consideration the level of mold YOU might not be able to tolerate 

Choose someone who has a lot of training and understanding of the impact of mold on YOUR types of health conditions.  

Look for someone who attends the medical mold health conferences and is always expanding their training and knowledge. 

7. Deciding the mold levels indoors are OK if the indoor levels aren’t more than outdoor levels 

Many mold inspection and testing companies compare indoor and outdoor levels.   

They’re looking to see if the level of mold inside the house is higher than outdoors (or equal to outdoors). 

Many inspectors will say that if your indoor levels are less than the outdoor levels, then you’re fine! 

This doesn’t make sense to me, though. 

This is how I think about it.  

It’s like if you have 10,000 cockroaches outside your home, and only 500 cockroaches inside your home—you still have a cockroach problem!   

Meaning, if you’re sick from toxic mold, it doesn’t matter how much mold there is outside. If it’s too much for your body, it’s too much.   

These areas in particular have a lot of indoor mold issues: 

  • Florida 
  • Texas 
  • The Midwest 
  • The South 
  • Any coastal areas  

These are basically anywhere that’s not a desert area.   

Mold testing and remediation can be very confusing.   

But you don’t have to make these mistakes. 

90% of our clients have had toxic mold in their home. It can feel overwhelming, but you don’t have to do this alone. 

This is why I’ve included a module on home testing basics in my MC360™ Precision Mold Master Class to get you started.   

I’ll also help you with information on how to pick out a qualified mold inspector. You’ll learn about this and even more about mold detox! 

References for Top 7 Home Mold Testing Mistakes – What to Know if You have Mast Cell Activation Syndrome and Histamine Intolerance

Damstra, T. (1978). Environmental chemicals and nervous system dysfunction. The Yale Journal of Biology and Medicine51(4), 457–468. 

Heindel, J. J., & Blumberg, B. (2019). Environmental Obesogens: Mechanisms and Controversies. Annual Review of Pharmacology and Toxicology59, 89–106.  

Luo, J., Hendryx, M., & Ducatman, A. (2011). Association between six environmental chemicals and lung cancer incidence in the United States. Journal of Environmental and Public Health2011, 463701. 

Post, C. M., Boule, L. A., Burke, C. G., O’Dell, C. T., Winans, B., & Lawrence, B. P. (2019). The Ancestral Environment Shapes Antiviral CD8+ T cell Responses across Generations. iScience20, 168–183.  

Weinhold, B. (2007). A spreading concern: inhalational health effects of mold. Environmental Health Perspectives115(6), A300–A305.  

Yorita Christensen, K. L., Carrico, C. K., Sanyal, A. J., & Gennings, C. (2013). Multiple classes of environmental chemicals are associated with liver disease: NHANES 2003-2004. International Journal of Hygiene and Environmental Health216(6), 703–709. 

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