Home Testing ABC's: What Makes a Good Inspection

Have you ever wondered what makes a good home inspection? Dr. Matt Pratt-Hyatt goes into great detail about thorough testing and analysis of an indoor environment and the importance of testing. To learn more about the different testing options, read on.

Hello Everyone,

Today’s topic is going to be home and environmental testing and environmental treatment.  In this post I will first outline how mold and mycotoxins in buildings is a national problem.  I will then talk about which molds and mycotoxins are the most problematic, how an inspector should test for them, and finally how remediation should be conducted.

One of my biggest pet peeves is hearing constantly from some in the medical community that mycotoxins do not come from home exposure but only come from food.  However, almost everyone reading this blog post probably lives in a country that spends millions of dollars (if not over a billion) per year on mycotoxin detection and regulation.  Various types of food are regulated by multiple different agencies.  Each agency has their own limits.  However, there are strict limits on cereals, nuts, milk, coffee, cottonseed, and other foods.  Estimates of revenue lost from products being contaminated by mycotoxins range from  just over a million dollars per year to over 1.5 billion per year(1). With the number of resources poured into testing and monitoring the most likely source of mycotoxin exposure in developed countries is from homes, workplaces, and schools.

Water damage occurs through two main sources, which are maintenance issues and natural disasters. Floods and hurricanes are easy to understand as water damage sources, however everyday occurrences such as cooking, showering, and laundering as sources of mold might be harder to understand, but could be contributing to mold if the conditions are optimal.  Another important factor in assessing mold growth risk is the type of building material used in a home.  A study from Tuomi et al looked at how much mycotoxins were able to be produced on different building materials (Table 1)(2).  The results were very dramatic in that cellulose and gypsum produced a lot more mycotoxins than samples made of mineral wood or plaster.  This demonstrates that dry wall, which is frequently used in newer homes is much more susceptible to mold growth.

Table 1: mycotoxins and building materials

This goes against another frequent myth that I hear which is “well I have a newer home so I can’t have mold” which is not actually true.  I see positive results on houses from 2-15 years old a lot more than 50 years or older.  Another good paper that I often refer to is from Andersen et al (3), which has a good table which I have labeled Table 2.  In this table you will find the frequency that different molds are found in homes.  From my experience I think these data are fairly accurate.  I tend to find Penicillium and Aspergillus as the two most common pathogenic molds in homes.  One excellent but not very well known papers in the last ten years in the mold field has to be the Murr et al paper (4).  The conclusion from this paper was “Seven fungi were found in very high concentrations in the sinuses of some CIRS patients.”  This can be summed up in what I will be labeling table 3.  This paper demonstrates that patients that have chronic rhinosinusitis have higher amounts of mold spores in their nasal cavities.  This was later confirmed by a Brewer et al paper (5).

Table 2: Frequency at Which Molds are Found in Homes

Table 3: Chronic Rhinosinusitis Patients and Mold Spores

Ok, so you have mold symptoms (described in previous blog) and you suspect that you and your family might be exposed to mold and/or mycotoxins.  What do you do?  There are two steps that need to be done.  Step one is to test everyone in the house using a urine mycotoxin analysis.  The reason why I suggest testing everyone in the house is that everyone excretes the toxins at different rates and some individuals are poor excretors, which means they don’t detoxify well.  Hopefully testing everyone will produce one person in the house who is excreting if mold and mycotoxins are present.  If everyone is negative, then maybe the house is clean of mold and mycotoxins and maybe we have a VOC (volatile organic compound) problem (I’ll talk about this in a later blog).

Step two (if someone in the house is positive for mold or has mold symptoms) is to analyze the home.  Finding the source of mold exposure is very important because a person cannot properly detoxify if they are continually exposed to mold and mycotoxins.  Current exposure is the number one culprit; however, we could also be dealing with lingering past exposure or colonization (more on this in later blog).

When analyzing a home, The Mold Pros (TMP) focus on the 3 M’s, which are Moisture, Mold, and Mycotoxins.  One important number is the water activity (aw) ( aw x 100 = % relative humidity at equilibrium) and the longer a materials aw is over 0.75 the greater the risk for fungal growth(6).  This explains why we have the most mold clients in Florida, the Pacific Northwest (Seattle, Portland, Vancouver), and the Gulf of Mexico region (Houston and New Orleans), which are all high humidity areas.  However, I have consulted on mold cases from every state in the US because construction and maintenance issues are not tied to a particular geographic region.  Studies indicate that moisture damage and mold in the main living areas of the house are the most correlated with adverse respiratory effects (7-9). In addition, how much moisture damage in the building are also correlated with the harmful outcomes for those that live/work in the building (10).  These problems can be found any part of a home/business/school; however, problems have been found in some areas more than others.  In Figure 1 from Becher et al. we can see that a majority of problems can be localized to the basement, attic, and bathrooms (11).  Our technicians spend as much time as necessary to do a thorough inspection in the structure.  We utilize state of the art equipment to find hidden moisture that may be behind walls and difficult to find.  Examples of some of the equipment that we utilize are infrared thermal cameras, moisture meters, and hygrometers.  As seen in Figure 2 you can see how we utilize our infrared cameras to find water intrusions in a building.

Figure 2: Infrared Camera Usage

The second M in our process is mold.  There are five main tests options for testing mold, which are spore traps, surface sampling, ERMI, HERTSMI-2, and EMMA-part 1.  I will detail out the strengths and weaknesses of all of these options.  The first two tests are spore traps and surface sampling.  These utilize microscopes to identify which types of spores are in the home.  The spore traps are set up throughout the home and will catch spores that are currently airborne in the home.  However, if the mold is not currently releasing spores than this test could provide less accurate results.  Surface sampling often refers to tape samples, where you place tape over a sample and then send the tape to be analyzed under the microscope.  This is helpful in identifying visual molds that are in the home.   The final three tests are PCR (polymerase chain reaction) test which looks for DNA from fungal species in dust samples.  The ERMI test is based on data from the EPA and the 2006 HUD American Healthy home survey.  There are 36 different molds in these tests.  There are 26 water damage molds and 10 common molds.  The benefit of this test is that the client receives a lot of data.  The downside is that some remediators scare clients with results that show high amounts of common molds.  One additional benefit of a ERMI is that you can calculate out a HERTSMI-2 score with these data.

HERTSMI-2 (Health Effects Roster of Type-Specific Formers of Mycotoxins and Inflammagens-2nd version) was developed by Dr. Ritchie Shoemaker to look at what he decided were the five most dangerous molds.  The data from this report can be used to produce a score by using the spore counts from the five different species, ie:  A spore count of Aspergillus versicolor of over 500 will be 10 points.  Some individuals use a score of 5 and below as safe, others use a score of 10.  The big downside of the HERTSMI-2 is that many pathogenic species of mold are left out of this analysis.  Through my studies I have seen that Penicillium species are one of the most common sources of mold illness (also see table 1 and 2).  Ochratoxin A, the most common mycotoxin found in humans, is produced by species of Penicillium.

The final mold test is the EMMA-part 1.  I call this part 1 because the EMMA is actually two test, a mold test and a mycotoxin test.  The mold portion is currently 11 mold species.   It is my opinion this is a comprehensive test, however, like the HERTSMI-2, they need to add Penicillium species to the test.

The 3rd M in our inspections is mycotoxins. These are the toxins produce by mold (see previous post).  When mold feel threatened, they produce these metabolites.  The types of toxins produced are dependent on the species of mold, the environment the mold is growing, and the food source.  The second part of the EMMA from Realtime Lab is an environmental mycotoxin assessment. This is the only lab that performs this function, which is quite necessary for a proper inspection.  Mycotoxins, which are molecules, are over 1000 times smaller than spores, which are cellular.  Mycotoxins have the capacity to infiltrate areas of a building that spores may be unable to reach.  In many instances, especially with stachybotrys, you will not find mold spores in the main living area, but you will find mycotoxins.  This is because spores are multiple folds larger than mycotoxins and many instances, they are sticky.  Spores can easily be trapped behind a wall but can still affect the inhabitants because of toxins they release.

If your home comes back positive for mold or mycotoxins, then a remediation will be needed.  We have a multi-pronged approach to fixing buildings.  One of our sayings is “we right-size the treatment,” which means that we do not do any work which we do not think is absolutely necessary.  This is the reason for doing the spore traps and surface testing. These two tests allow us to assess which rooms need to be prioritized.

Treatment of homes contains multiple parts.  Part One is removing the mold.  This involves sanding, pulling out damaged material, and ULPA filtration (which is better than HEPA).  Part two is removal of the mycotoxins.  This is done through our proprietary formulas surface guard and airguard (Link).  These formulas use enzymes produced from bacteria to degrade the mycotoxins.  This allows us to clean a property without using strong chemicals, which many of our clients are sensitive. This process is easily explained in Figure 3 below.

Figure 3: Enzyme Breakdown of Mycotoxins

Recent studies have shown that these enzymes can be very efficacious in the removal of mycotoxins.  As seen in Table 4, which is from Lyagin and Efremenko, there are three different enzyme classes that are very good at removing mycotoxins (12).  Utilizing this method, we are able to degrade mycotoxins throughout the house without exposing the home to harmful chemicals and reducing the amount of tear out needed.  Part Three is prevention.  We utilize environmental scientist to develop a plan to prevent future outbreaks.  This can involve building structural changes, increase ventilation, or installation of the EZ Breathe system (LINK).  This inexpensive system helps to dehumidify the home and to remove other potential toxins.

Table 4: Enzyme breakdown of Mycotoxins

I hope this information all of you determine how to move forward in your quest for better living conditions.  We are happy to help assist you in any part of the process.  Please come back for more information later on dealing with environmental illness.


  1. Zhang, K. Banerjee, A Review: Sample Preparation and Chromatographic Technologies for Detection of Aflatoxins in Foods. Toxins (Basel) 12 (2020).
  2. T. Tuomi et al., Mycotoxins in crude building materials from water-damaged buildings. Appl Environ Microbiol 66, 1899-1904 (2000).
  3. B. Andersen, J. C. Frisvad, I. Sondergaard, I. S. Rasmussen, L. S. Larsen, Associations between fungal species and water-damaged building materials. Appl Environ Microbiol 77, 4180-4188 (2011).
  4. A. H. Murr et al., Some chronic rhinosinusitis patients have elevated populations of fungi in their sinuses. Laryngoscope 122, 1438-1445 (2012).
  5. J. H. Brewer, J. D. Thrasher, D. Hooper, Chronic illness associated with mold and mycotoxins: is naso-sinus fungal biofilm the culprit? Toxins (Basel) 6, 66-80 (2013).
  6. K. F. Nielsen, G. Holm, L. P. Uttrup, P. A. Nielsen, Mould growth on building materials under low water activities. Influence of humidity and temperature on fungal growth and secondary metabolism. International Biodeterioration & Biodegradation 54, 325-336 (2004).
  7. A. M. Karvonen et al., Moisture damage and asthma: a birth cohort study. Pediatrics 135, e598-606 (2015).
  8. P. V. Kirjavainen et al., Microbial secondary metabolites in homes in association with moisture damage and asthma. Indoor Air 26, 448-456 (2016).
  9. K. Mustonen et al., Moisture damage in home associates with systemic inflammation in children. Indoor Air 26, 439-447 (2016).
  10. J. H. Park, P. L. Schleiff, M. D. Attfield, J. M. Cox-Ganser, K. Kreiss, Building-related respiratory symptoms can be predicted with semi-quantitative indices of exposure to dampness and mold. Indoor Air 14, 425-433 (2004).
  11. R. Becher, A. H. Hoie, J. V. Bakke, S. B. Holos, J. Ovrevik, Dampness and Moisture Problems in Norwegian Homes. Int J Environ Res Public Health 14 (2017).
  12. I. Lyagin, E. Efremenko, Enzymes for Detoxification of Various Mycotoxins: Origins and Mechanisms of Catalytic Action. Molecules 24 (2019).

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