Here we distinguish between
1.
tests to identify mold in a building and
2.
procedures to determine whether or not there is a mold contamiantion problem in a building.
Following that distinction we continue by listing the specific reasons to test for mold or cases when mold testing is appropriate and useful. In this article series we discuss the validity of nearly all of the popular mold testing methods currently in use, pointing out the strengths and weakness of each approach to mold sampling in the indoor environment, beginning with air sampling for airborne mold levels indoors. The appropriateness of testing at all is discussed on this and other pages at our website. Because mold test validity and mold test accuracy are often confused, readers should also see
ACCURACY OF VARIOUS MOLD TEST METHODS. People who need to conduct mold inspection and testing indoors should see
MOLD TEST PROCEDURES and
TECHNICAL & LAB PROCEDURES.
We are "making up" this temporary distinction to make clear an important point.
Mold Testing a building for the presence or absence of a problematic level of mold is unreliable if by "testing" one means a simple air test, an arbitrary surface or vacuum test, a swab test, or any culture method used alone and without a careful and complete inspection of the property. In particular, failure to detect problem levels of problem mold with an air, culture, swab, PCR or similar test (used alone) is not sufficient to conclude that there is no problem.
1. Airborne particle levels vary widely over short time intervals. What's in the air in a building varies enormously, possibly by a factor of thousands, over just a few minutes, depending on things like the level of activity, mechanical disturbance of dust, fans being turned on or off, hot air heat or central air being on or off, and more subtle changes in humidity, etc.
2. Cultures whether from a "home test kit" culture plate or a swab are unreliable as a characterization of presence or absence of mold because first, only about 10% of all of the 1.5 million mold species on earth will grow in any culture under any condition, second because what grows on a particular culture may be what likes that culture not what is the dominant problem, and third, because accurate speciation of some of our problem groups such as Penicillium sp. and Aspergillus sp. require arduous multiple cultures under very controlled conditions for reliable results.
3. PCR tests are highly accurate in identifying individual molds, if you know what you're looking for. PCR is not reliable as a broad spectrum scan to find what's in a building.
Mold Problem Identification, as we are speaking here, is an important part of a building investigation for mold (or other allergen) problems. By this we mean, an investigator should be charged to identify the presence of problematic mold, including no less than the following: first, the evidence that problematic levels of mold are present and that the predominant genera/species are ones which can be expected to be toxic or highly allergenic; second, the evidence that a large problem reservoir exists; third, the location(s) of the problem reservoir; fourth, the underlying causes for the presence of the problem reservoir.
This information permits preparation of a remediation plan to specify the cleanup needed and the building repairs needed to avoid simply producing more mold.
Key in a Mold Problem Identification investigation is the actual visual examination of the building, its history, its leaks, and other physical evidence. As a part of such an investigation, samples are collected of visible mold to distinguish cosmetic from problematic material, and other samples might be collected to examine the level of moldy dust settled in building areas where mold is not present. Additional samples may be collected for comparison baselines such from outdoor areas or from non-complaint areas in the problem building.
A thorough building investigation will include sampling or "tests" to identify the presence of mold and to identify the dominant problem molds by genera and often species. By contrast, a quick and simple "mold test," particularly a random spot check, is of little value by itself: grabbing a 90 liter air sample or putting a settlement plate in a closet for an hour is not a reliable building characterization for mold, and a tape sample of the single square foot of mold in a building is unnecessary.
Clean up small areas without testing: If there is no large mold area, no leak history, no at-risk occupants, in sum, if you simply have a little moldy area, just clean it up, and spend your "test kit" money on cleaning supplies or dinner out. Small amounts of mold can often can be cleaned-up by the occupant or owner provided that person has no special allergy or risk regarding mold. Some states define "small" as less than 30 sq.ft. of contiguous mold. Your own area may use a different criterion. Larger areas of non-cosmetic mold are likely to require work by a cleanup professional.
