DNA-based mold testing uses a scientific method called MSqPCR (Mold-Specific Quantitative Polymerase Chain Reaction) to detect and measure mold DNA in household dust. This approach doesn’t rely on live spores or visible mold growth—it identifies mold that has been present in the home at any point, even if it’s no longer active.

The idea is simple: mold leaves behind genetic material that settles into dust. By analyzing a dust sample, the lab can tell what types of mold have been in the environment and how much of each type is present. This makes DNA testing especially useful for understanding long-term exposure, assessing the home’s overall mold burden, or evaluating risks in homes with medically sensitive occupants.

Tests like ERMI, HERTSMI-2, and Fungi 10 are the most common DNA-based options for residential use. Each has a slightly different purpose and scoring method, which we’ll cover in detail in the lessons ahead.