How DNA Analysis Works - And Why It's Better for Detecting Home Molds

What Does DNA Have to Do With Mold in the Air?

Every mold spore carries a distinctive genetic sequence. When molds release spores and other microscopic material, those airborne particles carry fungal DNA with them (molds are fungi). By collecting particles from the air and analyzing the DNA they contain, it is possible to identify which molds are present and estimate their concentrations.

DNA analysis works by reading a molecular fingerprint. Traditional microscopy relies on the visible shape and structure of a spore, but many molds look similar under a microscope and cannot be reliably distinguished at the species level. DNA sequencing identifies molds using their genetic information, providing a more specific and standardized approach.

How Is This Different From Mold Tests Available at Hardware Stores?

Many consumer mold tests use settling plates: open agar dishes that passively collect spores before being incubated to grow visible colonies. These tests have several significant limitations.

Settling plates primarily capture spores that happen to land on the dish during the collection period. They may miss smaller particles that remain suspended in the air and are more likely to be inhaled. Because the tests depend on organisms growing in culture, they can also fail to detect nonviable spores and fungal fragments, which may still contribute to allergic or respiratory symptoms.

Most importantly, a settling plate may simply confirm that mold spores exist in a home—which is true of virtually every indoor environment—without providing clear information about the types or concentrations present. DNA analysis can distinguish among molds with different environmental and health relevance, including genera such as Alternaria, Aspergillus, and Cladosporium.

Can DNA Testing Detect Mold When There Is No Visible Growth?

Yes. Mold does not need to be visible for spores or other fungal material to be present in indoor air. Growth may be concealed behind walls, beneath flooring, above ceilings, inside HVAC components, or in other areas affected by moisture. Spores can also travel from basements, crawl spaces, attics, and outdoor air into occupied rooms.

DNA-based air testing can detect airborne fungal material even when the source is not immediately apparent. The results cannot identify the precise location of hidden growth on their own, but they can show which molds are present and help determine whether further moisture investigation or professional assessment may be warranted.

How Does Boulder Blue Collect the Sample?

The Boulder Blue kit includes a compact fan device that actively draws air through a collection filter. The fan runs for two hours in the area of the home being tested. This active sampling method collects a standardized, high-volume air sample that is more representative of what is circulating in the room than passive settling methods.

Once sampling is complete, the filter is shipped to Boulder Blue’s laboratory in Boulder, Colorado. At the lab, DNA is extracted from the collected biological material and analyzed using a next-generation sequencing pipeline. The results are matched against curated reference databases of known molds, concentrations are quantified, and the findings are compiled into a detailed report.

What Does the Report Show?

Each Boulder Blue report includes a summary AirScore—a calibrated index of overall airborne mold load—along with a detailed breakdown of the molds detected, their measured concentrations, and context about their potential environmental and health relevance.

The report also provides guidance about possible sources and practical next steps based on the findings. Because air testing cannot determine the exact location of a moisture problem by itself, the results are most useful when considered alongside the home’s history, visible conditions, odors, and any signs of water intrusion.

Reports are designed to help homeowners make informed decisions about their living environment. They may also provide useful supplemental information for healthcare providers evaluating a patient’s potential mold exposures.