ERMI Dust Test Interpretation

So you did an ERMI Mold Test, now what?

FAQ

The ERMI (Environmental Relative Moldiness Index) is a DNA dust test that identifies and quantifies 36 types of mold using advanced qPCR technology. Instead of air, it analyzes settled dust, where mold spores, mold fragments, toxins & byproducts of water damaged buildings naturally accumulate over time.
This test helps us begin building your risk profile, understanding the level of health exposure in your home, and determine whether you may need to hire additional professionals (like a mold inspector or HVAC specialist) as part of Phase 1 of your investigation.
It's not meant to answer everything, it’s your starting point.
Not at all. We hear this all the time. Unfortunately, many people are told, “You’re fine, your air test was clear,” and they move on, only to keep struggling with symptoms for years before circling back to mold.
Here’s the truth: air testing is not designed to assess health exposure. It only shows what’s floating in the air at that moment, not what’s settled, hidden, or fragmented.
It misses:
1. Mold fragments (often more inflammatory than spores)
2. Heavy, sticky spores like Stachybotrys
3. The species of mold (which matters for toxicity and risk)
It’s not a bad test, it’s just the wrong tool for the job. That’s why we start with DNA dust testing. It looks deeper, tells a longer story, and helps us assess what your body’s really been exposed to.
No, ERMI or ERMI Plus doesn’t identify where the mold is growing. It’s not a source-locating tool.
Instead, it helps us understand whether there’s enough mold exposure in the home, past or present, to warrant further investigation. It gives us context for your symptoms, your space, and your history, so we can determine if Phase 2 (like hiring an inspector) is necessary.
Think of it as a first layer of intelligence, it helps us assess risk, not diagnose locations.
To use it properly, we always interpret it alongside your intake, symptoms, home details, and goals. Without that context, it’s just numbers on a page.
No. ERMI detects the DNA of molds present in your dust sample, but it can’t tell you which ones are living, dead, or dormant.
That might sound like a limitation, but in reality, health symptoms aren’t just caused by living mold. Much of what affects sensitive individuals are fragments, toxins, and residue left behind by mold that’s no longer alive, or may never have been alive to begin with (like mycotoxins).
ERMI gives us a total exposure snapshot, not just a viability report.
It tells us which molds are present in the home environment, regardless of their growth stage, so we can evaluate overall contamination levels, how those molds may be affecting your health and whether there’s enough exposure to warrant an inspection.
No—you’ll get a copy, but that’s not the same as interpreting it.
Think of it like getting lab work back before your doctor explains it: you’ll see what's “high” or “low,” but you won’t know what it actually means for your situation.
That’s the difference between reading and interpreting.
Reading is surface-level—anyone can compare numbers to a chart. But interpretation requires context:
1. Your health history
2. Your climate
3. How the home is maintained
4. Prior Water Damage
5. Renovation or Remediation Events
6. Cleaning habits
7. HVAC system info
8. Sampling method
9. Your Symptoms, Susceptibility, Sensitivity
10. And how all of this connects to your current symptoms
This is where most people go wrong.
Sadly, even doctors & practitioners misread this test, especially when they rely on the ERMI score—which is outdated & not designed for this use. (Fun fact: “ERMI” technically refers to the score index only—not the actual test methodology itself.)
That “ERMI Index score” was created for EPA research in a narrow study design. We use this DNA testing off-label in a completely different way, and the score doesn't apply to real-world, health-based decisions.
So yes, you’ll see numbers. And you may see color coding that says some are low, medium & high.
But those numbers mean nothing without the full story. And when people try to make decisions—like leaving a home or throwing out all their belongings—based on an out-of-context ERMI score, they often end up overwhelmed, misinformed, and making choices from fear instead of facts.
That’s why we don’t just hand you results.
We teach you what they actually mean—and what to do next.
Definitely, which is why we send crystal-clear directions, written by our founders PJ and Peter Harlow. They’re simple to follow but professionally precise.
Some labs give overly dumbed-down instructions to avoid user error, but that can backfire. It doesn’t just lead to poor data, it can actually spike your results or skew them low depending on what’s interfering.
Here’s what to avoid near your sampling spot before testing:
- Bleach or chlorine products
- Rust or iron oxide dust
- Essential oils (especially tea tree)
- Paints, clay, or gypsum dust
- Urine, blood, or heavy oils
- Not Enough Dust: These tests require a minimum amount of fine dust (not hair or lint). If your sample has too little, the lab may not be able to run it—or you’ll get underreported results.
- Testing actual Mold
- Sampling from a New Construction
- Using this testing for PRV/Post testing or sampling a home that was just remediated
And remember, location matters. Sampling the wrong area can downplay a serious problem or exaggerate a minor one. That’s why our protocol walks you through exactly where and how to collect, so you get clear, usable results.
No, and here’s why.
This test analyzes mold DNA in settled dust, not what’s floating in the air right now. That dust gives us a long-term view of your home’s microbial activity, reflecting past leaks, seasonal changes, HVAC patterns, and contamination you might not even know about.
When people clean and wait 4–6 wks to collect “fresh” dust, they risk missing critical exposure history. Unless your symptoms started in that same short window, fresh dust doesn’t reflect what your body’s been reacting to.
Many cases of mold-related illness stem from chronic exposure to fragments, toxins and spores from old or hidden sources—not always recent growth.
So no, don’t deep clean. This isn’t the time to scrub baseboards or go hard on dusting. Just live normally and collect from your regular living areas—don’t overthink it. (We will instruct you with all the details)
The dust that’s already there holds the history we need to understand what’s really going on.
We don’t typically recommend it, and here’s why:
This test isn’t meant to find mold. It’s meant to screen your whole home’s fungal fingerprint and see if something’s off, like abnormal levels of water-damage molds.
If you test just one room, you lose the big picture. Mold fragments and microbial byproducts travel. So testing one area (especially one you’re worried about) gives you a skewed view, and may lead you down the wrong path.
This test is too valuable (and too pricey) to use for guesswork. If Phase 1 shows a problem, that’s when we move to Phase 1: targeted inspection, more testing, or deeper investigation.
Yes, basically. But here’s the nuance:
“ERMI” is actually not the test itself—it’s a scoring scale (Environmental Relative Moldiness Index). The real test behind the scenes is called MSQPCR, which detects mold DNA in dust.
So when we say dust testing, we’re just talking about the format: collecting dust instead of air or swab samples.
Different companies that sell this type of testing may add their own twist to the name or to the types of molds, bacteria or toxins included. Some include mycotoxins, others add bonus molds (like our ERMI Plus+). They may call the test different names, but under the hood, all of them are still using the same core DNA method and the same original 36 molds.
We know the “under 2” or “under this number” rules get thrown around a lot, but it’s a terrible standard. After reviewing thousands of ERMI reports, we can confidently say: lone numbers tell you very little.
Here’s why:
The ERMI score was developed by the EPA as a research tool, not a medical benchmark. It’s based on a specific vacuum sampling method and a scoring index (a table ranking homes by relative moldiness). But most people today are using cloths or Swiffer-style methods to collect samples—so the results don’t match how the original index was designed. It’s not apples to apples.
So when someone grabs a wipe sample, plugs it into the old EPA scoring table, and says, “You need to be under 2 to heal,” they’re misusing the test. That score can’t be applied universally like that.
What matters far more than the score is which molds show up, how much DNA is present, what your health picture looks like, and how the test was collected.
Bottom line?
That “under 2” number isn’t magic, and if someone’s using it as your mold healing threshold, they may mean well, but it’s not the full picture. You deserve a more thoughtful individualized approach. Healing is personal, and interpreting this test should be too. I have worked with some women that react to a speck of mold, and some men that don’t feel ANYTHING in a dungeon. That’s why we always recommend working with someone who understands the nuances and can look at your whole situation, not just a single number.
For most homes, yes, one test gives us what we need.
But if you have an unfinished basement, that space has its own environment and should not be included in your main sample. In that case, you may want to purchase a second test to sample the basement separately.
Larger homes (over 3,000 sq. ft.) or multi-story homes may also benefit from more than one test, especially if you’re trying to understand how exposures differ between floors. Still, one test is usually enough to get started and determine next steps.

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ERMI Dust Test Interpretation

What is the DNA Dust (ERMI) test?

My air test came back normal… but I’m still sick. Am I overreacting?

Can DNA Dust testing (ERMI) tell me WHERE the mold is in my home?

Will the DNA Dust test (ERMI) tell me which molds are alive, dead, or dormant?

Can I read the DNA Dust Testing (ERMI) results myself?

Is there anything I could accidentally do that would throw off my results?

Should I clean before my ERMI test? What about “old” dust?

Can I test just one room?

Is dust testing the same as ERMI?

My doctor said I had to have an ERMI score under 2 to be able to heal. Is that true?

Is one test enough?