ERMI testing is a DNA test method developed by the EPA to determine the relative mold burden of home in the United States. ERMI stands for Environmental Relative Moldiness index. The EPA surveyed 1,079 home across the United States for 36 different types of mold and analyzed the mold burden of those homes with the goal of compiling an index that could be used to help determine the potential moldiness of a home.
When an ERMI test is performed, dust is vacuumed up from the carpet in two different locations and collected in a cartridge. The composite sample is taken to a lab and compared to the data from the bank of surveyed homes and assigned a score that indicates the level of potential moldiness.
How does ERMI testing differ from other methods?
Air sampling and surface sampling methods are currently the industry standard for mold investigations and will reveal the current mold levels in the area tested, think of a snapshot in time.
ERMI testing is significantly different than the other methods of testing used in mold investigations because it reveals the history of mold exposure over time and can be an indicator of past water damage
Since both testing methods provide different information they can be used in tandem to establish a more comprehensive understanding of the mold activity in a given location.
Putting it all together
Testing is just one tool in the inspectors toolbox. The visual inspection of the investigation is a huge component of the process. Identifying mold levels is great, but determining the source is the most important part. During a mold investigation the inspector will perform a detailed inspection using infrared cameras and a moisture meter focused on water damage and conditions conducive to mold growth. Putting all the pieces together we can make a determination of the mold levels and probable cause.