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As I think about cutting edge information relating to mold, a recent client lament came to mind. My home inspection client was telling me of her frustration with doctors treating Lyme disease. Her son was going to one doctor, and her daughter to another. One physician was using antibiotics big time, and the other was using a more natural approach. From the mother’s research, she knew of other approaches as well. It seemed that every physician had his or her own perspective on treatments… yet her son, despite years of treatments, was still very ill.

Her words to me were, “Why can’t they all sit down in the same room and hammer this out?”

Sometimes I feel that way about mold testing, too. There’s Approach A and Approach B and Approach C, plus the opinions of the doctors, labs, and consultants who favor one or another approach. All of these may represent their own perspective on cutting edge information – or they may be operating under various misunderstandings and half-truths? Need I add, by the way, that the discussion we’re having here is beyond what the mold industry is doing?

In this section, I will try to summarize, simplify, and make sense of the various approaches to testing for mold, the various twists and turns of cutting edge information. Why is a consideration of this cutting edge information important?  Because trying to get well in a moldy house may be counterproductive. One doctor went so far as to remark, “Get rid of the mold, and the body can handle the Lyme.” Really?

Most of my referrals for home inspections come from physicians, especially physicians treating Lyme disease and the co-infections. These physicians understand that a person under their treatment may not get well if the person is living in a sick home.  A moldy home, for example, contributes to inflammation, which the physician is trying to treat. Let me summarize for you the different cutting edge approaches, at least the ones I know about to date:

Standard industry approach

A spore trap sample is taken on every floor plus the exterior, and swab or tape samples are sent to a lab from areas having visible mold. The mold industry is happy as long as the remediation area is clean and spore trap results are low.

Here are some shortcomings with that approach:

  • A lot of mold is invisible and can be missed.
  • Air samples are useful (and I do them all the time) but by themselves, they can miss mold. There are different reasons why mold releases spores. Sometimes you can see the mold but it is not releasing spores, and the air test results are fine.
  • Air samples do not tell you where the mold is growing. If you don’t know where it is growing, how do you know what to clean up?
  • Air samples miss mold in wall and ceiling cavities.
  • Spore trap sampling is not great for diagnostic purposes, because all the spherical spores are lumped in one category of “Aspergillus/Penicillium-like” spores.
  • Many inspectors are not aware of the latest research that confirms more accurate numbers are gotten from aggressive sampling, where dust is stirred up and the sample may be taken on the floor. More commonly, air samples are taken on tripods without stirring up dust and typically are artificially low.
  • At the end of a remediation project, air testing is typically done to confirm that mold is gone. But what if the negative air machine has just been turned off (or if it is still on)? Won’t the numbers be artificially reduced? Are they not testing the efficiency of the machine? Will numbers be as low 2 weeks from now?

    Here are some strengths of that approach:

  • Turn-around time is fast – usually 48 hrs after the lab gets the sample, unless a rush is required.
  • Often comparative numbers for Aspergillus/Penicillium-like mold are reasonably accurate. These are marker molds for dampness, leaks, and inadequate remediation jobs. If you were purchasing a house, you could expect that spore trap sample results would be somewhat higher in the basement than upstairs but if they are much higher, perhaps remediation might be needed. More investigation would be called for.

More in-depth on-site approach with many air samples and on-site microscope work (what I do)

Many air and surface samples are taken in an effort to find the sources of mold growth. Most houses have mold growth somewhere.  Some of these locations may require professional remediation but others might just be areas for home maintenance.

Out of more than 4000 homes I have inspected, I’ve found mold growth in all but about a dozen houses. Not too long ago, I inspected one of these rare “mold-free” houses. Some weeks afterwards, the homeowner called with the sad news that their hot water heater had failed, and he was now pulling out drywall. I said nothing for a moment and then quietly remarked, “How the mighty have fallen.” He laughed and swatted the ball back, “Yes, the first shall be last, and the last shall be first.” But he was doing the right thing: pulling out wet building materials before mold could grow, so his house would still have its good record of being mold-free, as far as we knew from test results.

CAP (DNA)testing

CAP testing is a new tool, which we have thanks to Dr. Joe Spurgeon. Think of it as shortened versions of the ERMI test, only without the often misleading ERMI or HERTSMI-2 score, which may not relate to the amount of mold in a home.

CAP is a dust sample, taken either by vacuuming or by use of a swab. The lab reports the numbers of mold particulates in “spore equivalents,” or bits and pieces of mold DNA. Based on comparison to a study of 93 houses, you can get an idea of the moldiness of your home or heating and air conditioning system.

Trivia: Did you know that house systems typically are not HVAC (heating, ventilation, and air conditioning) systems? Do you know why? There is no ventilation. Those of us who live in homes are assumed not to need fresh air or oxygen. What’s wrong with that picture?

Click for the instructions for CAP testing. (to be posted – please email me for a copy if you read this before they are posted). CAP testing is available for 2 species (which are a surrogate for the rest of the 36 species in an ERMI test) for $75, to gauge the moldiness of a house, or for 14 species for main species that address water damage molds for $140, or for other choices.

ERMI (DNA) testing is like CAP testing, only with an often misleading score.

  • Some microbiological labs offer ERMI testing (DNA) of dust samples.  The EPA (Environmental Protection Agency) developed this test for research purposes and issued a disclaimer that it was not tested or approved for residential use.
  • The test reads the DNA for 36 common indoor fungi. The hypothesis is that if the DNA levels are very low, the house does not have mold contamination. There is even a shortened version of the ERMI test for less money that reports on just five common indoor fungi, four of which may be associated with dampness conditions and one associated with leaks. A low score on the ERMI test or on the shorter Hertsmi-2 test gives the impression that the house is not contaminated with mold, but this may not be true.
  • Click here for Dr. Joe Spurgeon’s assessment of ERMI, or email me if the link is not yet up.
  • Click here for instructions on running your own CAP tests, or email me if the link is not yet up.  For as little as $75, you can send in a dust sample to get a sense of the “moldiness” of your home. For $140, you can get 14 common water-related species checked in the dust at your home, or coming through your HVAC duct. Then, once you have the numbers for the individual species, there are ways to interpret them to see where your home falls among 93 other tested homes.Some of my observations with ERMI/HERTSMI testing:
  • It is possible to get good ERMI test results and later find out that there is mold in the house, or to get bad ERMI results and not find mold.
    • At one house, I had done the inspection first and knew there was considerable mold in the basement. The ERMI test was done upstairs, in the living areas. Test results were fine. The ERMI had not picked up on the moldy basement.
    • At another house, I knew there was mold contamination in wall cavities. Same story. The ERMI missed that and reported good results for the house.
    • At another home, the homeowner did two ERMI tests, with two different labs. One set of test results was fine, and the second set was bad. I did a thorough mold investigation at the house, and my results supported the good test results. When I tried to understand the difference in results, I spoke with both lab directors. One director backed off, saying that he did not know how the second test was taken, or the conditions under which it was taken. The other director questioned the results of the first lab, suggesting that the calibration of their equipment appeared to be off.
    • At another home, 4 ERMI tests were done over the period of about 10 months, taking dust from the same 2 rooms. Test results were all over the map. The last 2 ERMI tests were done in the same bedroom, but on different sides of the bed, two weeks apart, with no cleaning in between. One result was fine; one result was not good. Neither the homeowner nor I could make sense of these test results.
    • ERMI can miss species of significance. For example, Aspergillus tereus is not on the list, yet I find that in many houses. However, the “answer” to that objection would be that if A. tereus is present, other molds on the ERMI list would also be present, so you would still get the guidance you need.

Testing for mycotoxins

Click here for Dr. Joe Spurgeon’s scholarly review of mycotoxins. Or email me if the link is not activated yet.

Click here for my interview of Joe Spurgeon.

At a physician’s recommendation, some clients have urine testing done through Real Time Labs that confirms or rules out exposure to mycotoxins from Stachybotrys and two Aspergillus species. Stachybotrys mycotoxins are so potent that they have been used in germ warfare. Because they can damage the body neurologically, they are on the short list of tested mycotoxins. Three other Aspergillus/Penicillium mycotoxins have been linked with neurological damage, with immune suppression, and with cancer.

To figure out if exposure to mold in the house maybe contributing to a positive urine finding, a dust sample, or piece of HVAC filter, can be gathered and tested for these three mycotoxins.  If the test turns out to be positive, a mold inspector may be called in to hunt down the mold and make recommendations for remediation. It should be pointed out that mycotoxins are in nature, and a positive environmental test does not confirm exposure for the person.

Limitations of mycotoxin testing

  • There are tons of mycotoxins out there. Mold research is in its infancy. Maybe there are other mycotoxins that are also significant for an individual than the ones tested here.  Conversely, maybe the dust test comes back clear – but there are other kinds of fungi in the house that are troublesome to health. This could result in false reassurance to the patient.
  • I have three clients now who have tested positive for trichothecene mycotoxins, but their homes have already been treated and there is little risk for more mold. In fact, in one case, DNA testing of dust had been done and was negative for mold. How can we explain these positive urine findings? The more common source of mycotoxins in dietary – such as from corn and wheat.
  • The lab representative indicated that exposure could have been 15 years ago, at this house or another residence, or a workplace, and the mycotoxins are still in the body. He described the excretion process (under physician treatment) as a bell curve, that is, levels of mycotoxins would rise in urine for possibly 2-3 years, and then there would be a decline. 
  • There are a lot of “ifs” connected with this testing – if this house, if that house, if the workplace or somewhere else.If the mycotoxin test is negative at the house, that is at least more useful. The homeowner doesn’t have to bring in a mold inspector…or does she? Think again.
  • Just because a few mycotoxins were ruled out, it doesn’t mean that everything is fine. Other species may be worse for the person’s health than the ones that make the 4 mycotoxins. In other words, the homeowner (and the physician) may have a false sense of security from a negative mycotoxin report.
  • To my way of thinking, the first step is an on-site in-depth mold inspection, looking for sources of mold growth and making recommendations for correction.

MVOC testing

  • Another type of testing relates to the measurement of gases produced from mold growth. These gases are called volatile organic compounds from mold, or MVOCs. These gases are biologically active, i.e., they can affect our health.
  • The gases are little studied, because of the cost of the lab testing. Some creative research started in the early days of mold studies, according to Brad at UL Environment in Marietta, GA, but when insurance companies stopped reimbursing for these tests, the research dried up. A MVOC test kit is available from Prism Analytical Technologies, This test also includes other sources of volatile organic compounds, such as from building materials and cleaning products.
  • You have the same dilemma with MVOC testing that you have with mycotoxin testing, ERMI testing, and air testing: Even if you get positive results, you do not know where the sources of mold growth are. A fishing expedition can get costly. One client asked, “What am I supposed to do to find the mold, tear my house down?” 

My concerns with MVOC testing

  • As with ERMI testing, there is a list of a given number of compounds that have been associated with mold growth, and not with offgassing from building materials. If some of these compounds show up in the report from MVOC testing, it is assumed that there is mold growth somewhere. The question of how much mold growth remains unanswered.
  • Test results can lead to a dilemma when one faces a fishing expedition for where mold might be growing. Also, the test results do not tell you how big an issue hidden growth might be. Is this hidden growth sufficient to cause homeowners to tear the house apart or to sell and move to another house? If they decide to sell, is this a disclosure issue for real estate purposes?
  • Installation of an ERV, an energy recovery ventilator, may be a better option for diluting volatile organic gases than to start digging around in wall cavities. (If your neighbor has a wood stove, the smell of smoke could be drawn in.) Of course, first have an in-depth mold assessment, preferably with an on-site microscope.


  • Some doctors are concerned about suspended microparticles (which would be detected through ERMI testing from dust collected on Hefty trash bags over 1-2 weeks). Dr. Spurgeon notes that microparticles are known to the indoor air quality industry but that there is no known technology to remove them. Misting would not do it.However, some doctors believe that misting does get rid of microparticles. If you are working with one of those doctors, then you might want a glycerin-based misting done at the end of the remediation process. Or, if you just want an extra step of treatment done for peace of mind, then consider a final misting with clear water with a little surfactant in it.

Summarizing these 6 testing options 

  • In summary, we see that even with more sophisticated testing, such as air testing and DNA (ERMI/Hertsmi and CAP) , mycotoxin, and MVOC testing, they all lead back to the same place: the need to identify where the mold is growing so that it can be properly removed.
  • These testing modalities have usefulness in some situations, some more than others, but none of them tell you enough by themselves so that you know what to do next. The exception to that may be CAP testing results for the HVAC system. In contrast, an in-depth approach to a mold inspection, such as I do on-site, is about as close as you can get to locating sources of mold growth, short of consulting a crystal ball. 

What should you do re: cleaning up mold at your home?

  • I’ll assume you had a mold inspection geared toward finding sources of mold growth first.
  • Next, before you hire a remediator, make sure that you understand the issues and options. Read this Cutting Edge section a few times. Confer with your physician, who may have recommended one or another type of testing for mold.
  • Make an informed decision of the best way to go, based on your health issues and your pocketbook.
  • Give me feedback as you can – since we’re all trying to learn what we need to know to foster health.

The evolving face of mold testing and remediation

  • You and I know about mycotoxins, microparticles, etc., now, but most of the mold industry doesn’t. This information is not good news for any of us, especially for the mold industry. Would a good solid lawsuit, won by someone who uses Greg Weatherman (developer of misting as a treatment for mycotoxins) as an expert witness, get the attention of the mold industry? Who knows? At a meeting, a physician informed his staff that an attorney told him not to even mention ERMI in court, since the EPA has a disclaimer on their website that ERMI was never meant for residential use.
  • The mold industry operates on a basic level: Look around. If you don’t see mold, it isn’t there. If you see mold, set up containment and remove contaminated material. If spore trap test results are reasonably low, they are happy. If spore trap test results are elevated, run the negative air machine some more and clean and re-test.
  • If you are confused about which way to go, think of it this way: If you need remediation at your home, where containment and negative pressure will be used, it would be a relatively simple matter while containment was still up, to do the misting and the wipe down. Misting, even with plain water and a little surfactant, is known to help clean the air.
  • But if microparticles and mycotoxins have spread through the house already (as established by DNA testing), then what a headache, at least if you are working with a Surviving Mold physician. Do you really want to hear about this?
    • Workers would have to go room by room, setting up containment at the door, misting and wiping down everything in the room. Upholstered furniture and mattresses? Out. Carpeting? Out. Clothing washed. And so on.
    • Perhaps this sort of misting and cleaning is necessary for some people to undertake so that their homes are healing places. I see my job as providing you with as much helpful information as I can so that you, with your physician, can make an informed decision.
  • So there you have it, cutting edge information that without doubt most mold inspectors and mold remediators aren’t familiar with – and may not welcome if they knew.
  • If you feel you must become more proactive than conventional remediators are, then you will have to be your own general contractor in supervising what you want done with mold remediation.

Now I’d like to show you what mold looks like under a microscope. Click on the next tab in this section. 

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