Testing For Mold? Avoid ERMI

ERMI’s glaring limitations will leave homeowners in the dust.

(Author’s note: I used to be an advocate of ERMI. The first test kit I created was ERMI-based. And we sold a lot of them. But after seeing how much fear and harm they caused, I shut it down. And that’s one of the big reasons we took great pains to create the GOT MOLD? Test Kit.)

In 2007, researchers at the Environmental Protection Agency (EPA) introduced the Environmental Relative Moldiness Index (ERMI) to numerically represent indoor mold contamination relative to the rest of the country. To this day, ERMI, which utilizes PCR testing to analyze DNA in dust samples, remains a research tool and has never been validated or endorsed by the EPA for at-home testing. 

In fact, in 2013 the EPA’s Office of Inspector General (OIG) warned that some companies were using and advertising ERMI inappropriately while referencing the EPA.

Makes you wonder: So why would these companies continue to advertise ERMI? And how has ERMI become so darn popular? Here are some reasons:

• ERMI’s popularity is largely attributable to Ritchie Shoemaker, a controversial physician no longer in practice. Shoemaker developed the Shoemaker Protocol to address Chronic Inflammatory Respiratory Syndrome (CIRS), a condition he coined that is brought on by biotoxin exposure from a range of sources, including moldy buildings.
• Shoemaker used ERMI, and a derivative he created called HERTSMI-2, in his protocol to evaluate the home environment.
• As the Shoemaker Protocol grew in popularity, many doctors began recommending ERMI and HERTSMI-2 to their patients, while also amplifying its supposed benefits.
• It has long been rumored that Shoemaker has an ownership stake in the specific lab he aggressively promotes, something he denies vigorously.
• Some doctors like to recommend ERMI, in part because it’s in the Shoemaker Protocol, but also because DNA and PCR-based technologies are considered cutting-edge and sexy.
• ERMI, however, is neither cutting-edge nor sexy. After 20 years, in an area of science (genomics) that has advanced at a blistering pace, it’s simply outdated and imprecise.
• Some companies falsely market ERMI as EPA-approved, and some medical professionals mistakenly view ERMI as a test panel for detecting toxin-producing molds, which it is not.

What’s going on: Why would the EPA refuse to endorse or validate technology developed in-house? The answer is simple: ERMI does not provide significant, if any, improvement over traditional mold inspections, and often fosters unwarranted fear and panic. Below we outline the myriad shortcomings of ERMI, and why it should not be an option for at-home mold testing. 

The technology is outdated

• Underlying ERMI is a DNA-based mold analysis method called MSQPCR, or Mold Specific Quantitative PCR. 
• Developed decades ago, MSQPCR analyzes settled dust samples taken from a building and focuses on just 36 species of molds.
• A selection of 36 molds is not a complete analysis, far from it. Newer research shows that ERMI covers less than 15% of molds commonly found indoors by more comprehensive DNA testing (amplicon sequencing).   
• Despite incredible advancements in DNA technology, MSQPCR tests have remained stuck in time, all but unchanged from the original patent application in 2002. 

The original study that formed the basis for ERMI was small and narrow

• MSQPCR was first rolled out in a 2004 study of just 37 homes in Ohio.
• This means the study’s data was derived from a scientifically insignificant number of homes from just one region.
• The EPA later extended its research, in 2007, to include 1,096 homes from across the country, but the results from the initial 2004 study provided the basis for ERMI’s selection of just 36 PCR targets.
• Obviously, important regional variations are lost in this approach.

ERMI disregards the geographical setting of a building

• Different geographical areas produce different molds, meaning certain types are prevalent in some locations and non-existent in others.
• Unlike mold tests that use spore traps, ERMI does not use an outdoor sample to compare against what’s found inside.  
• A log cabin on a heavily wooded lot has different spores in the settled dust than say those found in a New York City high-rise, or 37 homes in Ohio.

ERMI’s use of “composite sampling” lacks precision and specificity

• ERMI’s protocol takes two dust samples, collected from two different rooms in a building, and combines them into one sample before sending them to the lab.
• This kind of composite sampling makes determining the source of any potential mold issue impossible.
• “Which room has a problem?” is not answerable with ERMI. 

Dust testing often returns inconsistent, irrelevant and fear-inducing results

• ERMI-based products analyze settled dust samples, instead of directly testing the air.
• But what’s in your dust isn’t necessarily airborne, and does not equal exposure.
• Testing piles of settled dust may be a good way to identify household allergens, but those piles do little to identify an active mold issue. A wide variety of spores in dust is normal and does not necessarily indicate a mold problem. 
• And because dust samples carry a great deal of history—much of it irrelevant to a home’s current air quality—they often return alarmingly high levels of mold spores, especially in older homes. This can cause unnecessary panic which may lead to hasty and disruptive decisions.
• It’s extremely common for high ERMI scores to be unverifiable through a thorough inspection by a qualified professional, rendering the ERMI information not only useless but potentially counter-productive.
• For these reasons, it’s unusual for reputable, ethical professionals to use ERMI. 
• It is, however, a favorite among certain inspectors and mold remediation companies who capitalize on the fear it induces to justify extensive, costly—and often unnecessary—remediation projects.

ERMI preys upon public misconceptions about “toxic” molds

• Despite its original intent as a research tool related to asthma in water-damaged homes, ERMI has been hijacked (even by seemingly well-intended medical professionals) to detect the presence of mycotoxigenic species, aka “toxic molds,”—which it does not do, except for just a few well-known species.
• Though some molds are more disconcerting than others and anecdotally linked to more serious health effects, looking for just these molds can distract from the primary reality: indoor mold growth of any significance, regardless of the species, is a problem.
• ERMI is not a mycotoxigenic mold panel, nor was it intended to be. 
• Furthermore, there’s mounting evidence that any indoor mold growth has the potential to cause toxic exposures simply through the inhalation of the musty odor that the growth produces.
• Long dismissed as a mere aesthetic nuisance (“basement smell”), the compounds that comprise the musty odor—known as microbial volatile organic compounds (mVOCs)—are shown to have neurotoxic effects in animal studies. 
• Dr. Joan Bennett of Rutgers, a leading researcher in this field, has suggested an alternative name to properly recognize the hazardous potential of these chemicals: volatoxins. 
• All molds produce these compounds during active growth. 

The issue of subtracting molds [For the technically inclined]

• ERMI scores range from -10 to +30, with a low or negative number representing minimal mold contamination and a high number representing significant contamination.   
• To arrive at a score, ERMI uses a formula that adds together molds thought to be more common in damp/moldy homes (Group 1) and then subtracts the molds thought to be more common in a normal indoor environment (Group 2).
• However, newer research has found no apparent association between Group 1 molds and contemporaneous water damage (Adams et al, 2020). 
• Another problem with this formula is that high concentrations of Group 2 molds will lower an ERMI score, thereby creating the false impression that the molds in Group 2 are somehow a good thing. They are not. 
• A high indoor concentration of ANY mold is bad. Period.

The accuracy of MSQPCR is problematic [More technical jargon]

• MSQPCR, the test underlying ERMI, is not as accurate in the enumeration of spores as people expect it to be.  
• The ERMI research group reports a standard deviation of 3 for ERMI. But with 50% of all tested homes falling into an index range of -4 to 5, a standard deviation of 3 is quite significant. 
• In other words, ERMI doesn’t count well.

In a nutshell: No single test can determine a building’s health or safety. Determining the health of a building, much like determining the health of a person, requires a multi-faceted approach. This approach requires the gathering of data and information from a number of sources. Mold testing can and should be a vital piece of the puzzle, so long as the data produced is accurate, relevant, and relatively easy to pinpoint. ERMI, despite its popularity, can stake no such claims.

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The GOT MOLD? Test Kit

Until recently, testing your home for mold meant hiring a professional to collect air samples—often with a price tag in the thousands—and then crossing your fingers that this person had enough expertise, know-how and integrity to do the job right. It was (and still is) a process rife with uncertainty. As were the options for self-testing, which were abysmal. 

In the absence of a reliable and affordable DIY solution, and amid the public’s growing awareness of mold-related illnesses, emerged ERMI—an inherently flawed and increasingly outdated research tool never intended for individual at-home testing. But despite its shortcomings, ERMI is routinely misused by unaware homeowners, misrepresented by dubious inspectors and remediators, and promoted by well-intended medical professionals.

It’s time for that to change. 

The GOT MOLD? Test Kit was conceived after seeing countless people fall prey to junk science hardware store kits and ERMI. 

Spanning years of research and development from a dream team of scientists and engineers, the GOT MOLD? Test Kit is the easiest, most affordable way to test your air for mold—without the hassle and expense of hiring a professional or the concerns associated with ERMI. 

So check us out and let us know if you have any questions. We’re here to help.