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How to use adhesive tape to sample building dust, mold, or surfaces for particle identification:
This article explains the advantages and shortcomings of using adhesive tape to collect mold test samples (or virtually any other other dust or particle samples) from indoor surfaces. 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.
We discuss the use and limitations of bulk, surface, or tape sampling for mold testing in buildings. Bulk samples are samples of material taken by direct scrape onto
glass slides, by processing of sample materials, by pressing clear cellophane tape on a surface, or by using a special cassette and vacuum pump to vacuum a
surface. With owner permission, a sample of actual surface material is occasionally removed and brought to the lab for further analysis.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
Recommendations for Using Tape sampling for Testing Buildings for Toxic Black (or other) Mold
15th Annual North Carolina/South Carolina
Environmental Information Association Technical Conference
Myrtle Beach, SC
Daniel Friedman 23 September 2005, Updated 4/14/2009
Before you buy an over-the-counter or mail-in home test kit for mold you should read this article about using simple clear Scotch tape® in a simple dust or surface or mold sampling procedure that uses very inexpensive materials and, with intelligent selection of sample surfaces, can produce results of superior accuracy.
This article series presents a summary and critique of some popular methods used to examine indoor air quality to test for presence or absence of problematic levels of toxic or allergenic mold or other bioaerosols.
Our page top photo demonstrates that the tape sampling location is critical for accurate identification of particles or mold types in a building - each of the three tapes in this photograph collected an entirely different genera/species of mold.
We describe and critique specific "testing" or "sampling" methods used to
"test" buildings for mold in the course of a building investigation. The appropriateness of testing at all is discussed on this and other pages at
our website. We will review the following:
How to use adhesive tape for mold identification samples. How to use adhesive tape to screen building dust for mold or other particulate contaminants.
Use of adhesive tape to trace building dust particles to their source.
Why is tape sampling preferred during building air quality or mold investigations? Limitations of tape sampling for mold or other building particles.
What is Tape Sampling for Mold?
Bulk or surface samples are a key determinant in evaluating building condition, provided they are collected strategically and in accompaniment of a
careful visual inspection using good inspection methodology.
A casual look may find obvious black spores but miss more problematic light-colored fungal
colonies; a colony can, of course be hidden behind building walls or ceilings or under furniture.
Since random bulk samples offer a high rate of
false-negative (no problem) findings, they are not particularly useful. Samples are collected based on clues found during the visual inspection, and are
collected in multiples if variations in mold appearance or growth substrate make it likely that multiple species are present in a given area.
samples, such as of surface dust, are collected from sources known from experience to be more likely to represent ongoing conditions in the building.
These samples are examined to determine the dominant types of particles present. When dominant particles are allergenic or toxic, further investigation
or cleaning are needed. In some cases, recurrent presence of low levels of unusual particles (by species or type) may also indicate a hidden problem in
Inspectors or consumers who require examination of special samples (i.e. samples not on clear cellophane tape, vacuum cassette, or slides) should
contact us to make arrangements before shipping such samples to our lab. In addition to preparing high-power light-microscope slides from special samples,
we may use both stereo zoom microscopy and in some instances the construction of special particle-removal apparatus to study special samples.
Clear cellophane tape is pressed into a sampled surface, then removed and
affixed to a clean surface such as a plastic bag or a microscope slide for
mailing to a lab. The lab prepares the tape for microscopic examination.
mold genera and species identification the tape is examined in the laboratory.
Tape samples can also be cultured (see Culture discussion below). This is the
least-expensive collection method available, and is a preferred tool.
That article provides a detailed, step by step guide to using clear adhesive tape to collect particles from building surfaces to test a building for a history of exposure to airborne (and dust) presence of allergens, animals (dogs, cats, mice, rats, others), asbestos, cockroaches, dust mites, fiberglass, insect fragments, pollen, soot, or mold. Building dust samples can also be used to trace dust or problem particles to their source, such as insulation from damaged duct work, or in some cases, failing HVAC equipment.
Using clear adhesive tape pressed into a surface to be tested is the first
choice recommended method for identifying mold in a building, particularly when
combined with visual inspection as part of a mold investigation, per AIHA and
other expert sources. This method permits rapid identification of genera
(family name) and very often species (individual member name), particularly
when the mold sampled has uniquely-identifiable spores or where the sample
collects the conidiophore or spore-producing body as well.
In some cases genera determination alone is quite sufficient as the some of
the common problem-genera (Penicillium sp. and Aspergillus sp.)
do not have non-problematic members which grow in buildings. Speciation is more
likely to be needed when doing medical diagnosis. Tape samples can also be
cultured if additional speciation is needed. Since tapes can collect the
conidiophores and hyphae (when tape spot is chosen with some thought) they give
more data than an air or vacuum sample.
For building where large amounts of mold are found or suspected, tape
sampling is a qualitative approach which is usually quite successful in
addressing the basic question: is there a problematic genera which requires
professional remediation? Combined with a visual inspection to locate target
areas of risk and to find visible problems, it is the most essential component
of a building mold investigation and is the method recommended by experts
writing in the field and by the AIHA's own training materials.
Tape samples are the preferred method of collecting surface samples in
buildings. Tape pressed into appropriate portions of suspected mold growing on
a surface collects the most material from the surface and often includes
sufficient structural material to identify the dominant problematic genera and
A properly collected sample is likely to contain both fungal
conidia, conidiophores, and hyphae, the latter two of which are important aids
for speciation. Tape samples of building dust and even tape samples of moldy
carpet are also generally useful in this manner but have some limitations
A Guide to Using Tape Sampling for Determination of Mold genera and Mold species:
Nearly all building mold genera can be determined by light microscopic
examination of tape samples. In the majority of building investigation cases
the key question is "is there a problematic genera (toxic or allergenic)
requiring containment and professional remediation?"
This can almost
always be completely answered from genera alone. This is because within the
more common troublemakers, their non-problematic member species may not occur
in buildings. For example, Penicillium notatum, used for the drug penicillin,
does not grow in buildings! If you find Penicillium sp. in a building in
quantity it needs to be remediated.
Speciation of many mold genera can also be determined from tape sample
material alone in many but certainly not 100% of cases.
Some examples of easily
speciated molds from among the most common genera and species found in
buildings: Cladosporium sphaerospermum,
C. cladosporioides, Ulocladium chartarum, Taeoniella rudus, Pithomyces
chartarum, Stachybotrys chartarum, Chaetomium globosum, Chaetomium aureum,
Aspergillus niger are just a few examples.
Our photo (left) shows a nicely preserved conidiophore of Aspergillus niger on an adhesive tape sample.
A good mold tape sample which collects the conidiophore and
hyphae makes speciation possible for many molds. Many other airborne spores
appear in buildings and can be similarly speciated, but are not building molds.
Other airborne molds such as the Aspergillus and Penicillium families are probably
a sufficient hazard in buildings that if they are present in a large reservoir,
speciation is not needed to decide to remediate.
Shortcomings of tape sampling tests for Toxic Mold:
Everything depends on where
you stick the tape. Investigators and ordinary building occupants tend to
collect that which is easy to see - "black mold" and may miss more
important, more health-risky light-colored and highly airborne genera
(Aspergillus, Penicillium) which are also present but more difficult to
An expert looks for mold-suspect material that seems to represent the
dominant presence in an area by color, texture, and growing surface
material. It would be unusual for there to be only a single genera/species
of mold in a mold-problem building. Looking and taping requires some
guidance and education.
Some smaller airborne mold
spores do not settle out of air rapidly and might appear equally as
plated-out on walls as in dust on horizontal surfaces.
inspection to search for an unidentified problem source, samples of
surface dust may under-represent the presence of these molds, though where
a substantial airborne presence exists we have always found a surface dust
presence as well.
By contrast, properly collected tape samples from
visible mold growing on a surface does not suffer this shortcoming.
Speciation of genera may be
needed for special medical diagnostic reasons. From spores alone in any
sample method, two of the most widespread problematic genera can be
speciated only to a few cases. (Aspergillus
niger for example.)
for medical use, tape speciation of some genera is too limited, in
particular if the sample collects only spores - a problem which can occur
if tape is pressed into dust rather than into an area of growing mold, or
when tape of a mold colony is pressed into a spore-packed center of a
mature colony instead at the edges where the new colony growth and
conidiophores are easier to find. A little knowledge of mycology is useful
to professional building inspectors.
When growing conditions
become unfavorable some molds change form into an encysted or encapsulated
dormant state, forming fungal perithecia, cleistothecia, or pycnidia which
may be collected as "black stuff" from building surfaces
(particularly wood). While often one finds identifiable material among
perithecia that cant' be assured. Culturing of such samples may produce an
identifiable fungus if by luck the right culture media is selected.
Tape sampling is qualitative,
not quantitative. Most experts and competent labs will offer a description
of the density of fungal material found in the sample using
non-standardized terms like Level 1-2-3-4 or Light, Medium, Heavy, or
Dominant, Present, and Incidental.
These terms lack a standard definition
but are of some use provided the lab has and can provide their own
standard and definition.
In sum, the determination of the presence of a building mold problem (toxic
or allergenic) vs. cosmetic mold can usually be made from tape samples alone. Tape samples are preferred by the most experienced and trained professionals in the aerobiology field.
Or see MOLD LEVELS on SURFACES where we describe "How to Report Mold Levels on Building Surfaces Using Tape Samples of Indoor Surfaces and Indoor Mold "
Continue reading at TEST KITS for DUST, MOLD, PARTICLE TESTSfor a detailed, step by step guide to using clear adhesive tape to collect particles from building surfaces or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
where can I find a lab to tell me the contents of dust in my house?
I am interested in finding out the content of dust particles I continue to get in my house for the last seven years. With Aprilaire high efficiency air filters on each of my units, I don't understand the where the dust is coming from. I'm thinking if I know the content makeup, it may help to determine the source.
- need to know to collect a sample for content testing.
- need to know the cost per sample. - D.W. 2/22/12
Lab test fees vary by test lab, typically between $25 & 50. U.S. per tape sample for tape samples of surface materials, particles, dust or mold analyzed by light microscopy. In the header section of that article you'll also find links to helpful tips on inspecting your home and choosing a sample location.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home",
U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
"IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA
http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Allergens: Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
Allergens: WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests
Atlas of Clinical Fungi, 2nd Ed., GS deHoog, J Guarro, J Gene, & MJ Figueras, Centraalbureau voor Schimmelcultures, Universitat Rovira I Virgili, 2000, ISBN 90-70351-43-9 (you can buy this book at Amazon) - The Atlas of Clinical Fungi is also available on CD ROM
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention in Home Vegetable Gardens,"
Department of Plant Microbiology and Pathology,
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones