The Mold Test You Were Sold Online Was Built for Research, Not for You

Search “mold test kit” and you'll be offered ERMI, HERTSMI-2, and a menu of DNA-based scores promising a number that tells you how dangerous your home is. We looked at what regulators and standards bodies actually say about these methods — quoting them directly rather than paraphrasing.

What the EPA says about ERMI

The Environmental Protection Agency developed the Environmental Relative Moldiness Index as a research tool. The EPA does not validate it for routine public or consumer use. That's not our characterization — it's the agency's own position on a method that is marketed to consumers every day as a diagnostic.

What testing can and can't tell you

Air and surface sampling by an accredited lab has legitimate uses — confirming a suspected problem, or verifying that a remediation actually worked. What no test can do is convert a spore count into a personal health risk score. The CDC is explicit that sampling is generally not needed to decide whether to clean up mold: if you can see or smell it, it needs to be removed regardless of type.

The tell

Be most skeptical of a “free mold inspection” offered by the same company that wants the remediation contract, and of any test sold as a fear-to-fix funnel. In every state that licenses mold work, that inspect-and-remediate combination is illegal for a reason.