"Objective: The objective of this study was to develop screening tools that could be used to estimate the mold burden in a home which would indicate whether more detailed testing might be useful. Methods: Previously, in the American Healthy Home Survey, a DNA-based method of analysis called mold specific quantitative PCR was used to measure 36 molds in standard protocol dust samples. This resulted in a national index called the Environmental Relative Moldiness Index (ERMI). In this current study, two possible screening methods were considered: use of the vacuum cleaner bag dust rather than the standard protocol dust samples and reducing the number of molds needed to be quantified resulting in the creation of a simpler mold burden scale. Results: Comparison of vacuum bag and standard dust samples from 157 of the same homes demonstrated that most molds had higher detection rates in vacuum bag dust compared to athe standard dust samples but the ERMI values were still related to each other. The second approach to simplifying the screening for mold burdens produced a correlated (ρ=0.80) index to the ERMI called the American Relative Moldiness Index (ARMI) which requires the analysis of only 12 species. Conclusions:
Vacuum bag dust sample ERMI values were predictive in placing a home into the lower or upper 50% of
homes on the ERMI scale. If it is not possible to obtain athe standard dust sample, the vacuum cleaner bag dust may be a useful screening tool for estimating mold burdens in homes. If the standard sample is available and a simpler screening test is sought to estimate the mold burden in homes, the ARMI scale might be useful."
Translation: Using 2 methods of testing (vacuum and dust swab), It was found that both methods produced results although the vacuum sample picked up much higher mold levels (typical, since airborne molds follow the laws of gravity). The results were used to produce the ERMI scale that is used to determine if homes have an elevated mold level (up to 36 species). The EPA does not appear to be happy with detecting only 36 mold species and has developed another test to "reducing the number of molds needed to be quantified" under the banner of "creation of a simpler mold burden scale" and has formed the ARMI scale
which detects only 12 mold species. It appears that the EPA is recommending that a dust swab be used as the standard testing apparatus, "If it is not possible to obtain athe standard dust sample, the vacuum cleaner bag dust may be a useful" for use only in the ARMI test. It also appears that the vacuum cleaner dust sample is not as accurate as the dust swab sample. Unfortunately, the vacuum cleaner dust samples are exclusively used to determine whole house mold levels (via EPA protocol) using 2 samples from the "bedroom & living room" areas (and in some EPA publications the upper and lower floors - 2).
The EPA touts that during the EMRI tests between the vacuum and swab samples that "the ERMI values were still related to each other". Of course they are related to each other in types of mold species detected. Dusts (used for mold analyzation) in a building have a great tendency to remain exact in regard to "absorbing" the types of molds in the building. So it is no great scientific breakthrough when they do so.