In our first installation of this series, we talked about
the importance of including a control sample when taking air samples for mold
in a home or business. We learned that context is important when determining
whether or not we have elevated spores in a building, as mold is ubiquitous and
makes its way into our homes frequently in non-problematic levels. Today, we'll
discuss some of the types of mold tests that are utilized by industry
A cursory search of DIY home mold tests led me to a test
kit on a large online retailer. A quick review of the information left me in
awe of the misinformation presented. At best, the presentation of the
information is disingenuous. As I stated in the part 1 of this series,
different types of tests do different things. Without getting too deep into the
minutia, we'll cover the basics below:
Air Samples- Most air samples are taken with a spore trap
cartridge that is connected to an air pump. The spore trap has a thin sticky
material surrounded by a plastic casing. This trap gets connected to an air
tube the pulls air through the trap, so that spores that make their way through
will get stuck on the sticky material. The air pump is set to a specific
setting to maximize the capture of spores on the trap. These tests are good for
determining if there are mold spores present in the ambient air.
Tape Lift- A tape lift is a pretty basic sampling method.
It's a thick, pliable piece of plastic that has a sticky portion on one end.
These are used to test for settled mold spores on walls, above doors,
furniture, etc. The tape lift sample gets put onto a glass slide and sent to
the laboratory for review. May times, tape lifts are used to see if a property
has been remediated properly as we can test surfaces where mold spores were
Swab Samples- Swab samples are much like tape lift samples
in that they require the sampling technician to sample a particular surface,
such as a wall or piece of furniture. The big difference is that swab samples
are used to culture the mold spores that they capture. This cultured sample
given us additional identifying information so that we can determine the
particular species of mold. Air
Samples and tape lift samples will only get down to the genus level. We'll save the lesson in taxonomy for another day.
This is all to say that if you're allergic to a particular type of mold, swab
samples will give us the most accuracy in determining whether or not that
species of mold is in the home or business.
ERMI Testing Kit
ERMI Testing: These types of tests use collection of dust to
identify mold in a property. Originally designed as a way to correlate
childhood asthma with historical water damage information, ERMI tests use DNA
analysis of the sample to identify mold types. The limitation of ERMI testing
is that the results generally do not correlate with current conditions in the
home. They are good for providing historical information regarding molds that
were present in the home at some time. These tests are not indicated for
It's important to understand the limitations and strengths
of each of the testing methods as they have clear implications for the financial,
mental, and physical well-being of the homeowner. A professional mold assessor
would be unwise to utilize an ERMI test to identify current airborne levels of
microbial spores. Conversely, that same assessor would also not be doing right
by the customer if they utilized an air sample to gather historical data about
molds that have been present in the home over an extended period of time.
With at-home tests, we may be utilizing a testing method
that is not providing the type of information that we are looking for. We also
lack the professional judgment of a licensed assessor to guide the process and
interpret the results. Some at-home tests will utilize an ERMI-type dust
collection test when the homeowner really wants to know why their child is
getting sick so often. Unfortunately, this method of testing will not provide
the correct answer to the question the homeowner is asking. It will provide an
answer, but to an entirely different question. This is where interpretation of
a test used for the wrong purpose may cause the homeowner undue distress. Using
the proper testing methods with an assessor who can navigate the necessary
procedures and methods is important for answering the important questions that
customers are asking when we are dealing with microbial problems.
We'll continue this series in post 3, when we get into some
of the claims made by at home test kits and we'll see if they hold up.