Several mold testing methods are available, each with specific applications. Below are the most common types used by professionals:
Air Sampling
Air sampling is the most widely used method to detect mold spores in the indoor environment. A professional uses a pump to collect air samples, which are then analyzed in a lab to identify mold types and concentrations.
How It Works: Air is drawn through a cassette or petri dish containing a growth medium. The sample is incubated to allow mold spores to grow, then examined under a microscope.
Surface Sampling
Surface sampling involves collecting samples from visible mold or suspected areas, such as walls, floors, or furniture, to confirm mold presence.
How It Works: Methods include swabbing (wiping a surface with a sterile swab), tape lifting (pressing adhesive tape onto a surface), or bulk sampling (removing a small piece of material). Samples are analyzed in a lab to identify mold species.
Bulk Sampling
Bulk sampling involves removing a piece of material (e.g., drywall or carpet) from the home for lab analysis to determine mold contamination.
How It Works: A small section of material is cut out and sent to a lab, where it’s tested for mold growth and type.
ERMI Testing (Environmental Relative Moldiness Index)
ERMI testing is a method developed by the EPA to assess mold contamination in a home by analyzing dust samples.
How It Works: Dust is collected from surfaces (often via vacuum or cloth) and analyzed using PCR (polymerase chain reaction) to identify mold species and quantify contamination. Results are compared to a national database to calculate a moldiness index.
Culture Testing
Culture testing involves growing mold from samples in a lab to identify specific species and assess their viability.
How It Works: Samples from air, surfaces, or bulk materials are placed in a growth medium (e.g., agar plates) and incubated. Lab technicians identify mold types based on growth patterns.
