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What a Valid, Useful Mold Report Should Include

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This document provides a sample mold test lab report and discusses what to look for in a mold test report and how to interpret the data.

A mold test lab report can produce a lot of information. In fact it could sound overwhelming. Is there a mold or IAWQ problem? What is the evidence? Where is the problem source? What containment and cleaning are needed? What building repairs are needed to prevent future problems?

How will we assure that the field investigation work is properly done? How will we assure that the mold test lab work was actually done by an expert? Our reports also include professional photo documentation of our microscopic findings in the laboratory. .

Green links show where you are. © Copyright 2017, All Rights Reserved.

Purpose of Mold Lab Reports

Example mold air test report (C) InspectApediaA "bare" mold-lab report provided by an investigator who performed a "screening inspection" for mold, and who has not also performed a thorough visual inspection of the building is likely to leave the client with no idea about how to proceed, where the problem is, if any, and what to do about it. If you suspect that there is an indoor air problem in the building involving mold or allergens, you need to know the following:

  1. Is there a mold, allergen, or similar environmental problem in the building?
  2. If there is a problem, where is it and how big is it?
  3. What does the lab work indicate about the level of risk to occupants or workers? Are we looking at a "cosmetic-only" concern?
  4. What is the extent of demolition or cleaning needed, and based on the lab results, what is the level of containment and care needed?
  5. What needs to be changed or repaired on the building so that problems don't recur?
  6. And after the cleanup has been completed, was it proper and complete?

In other words, in exchange for being paid a professional fee to investigate a building, the investigator should provide accurate and useful diagnostic and prescriptive information to his or her client.

Example© Mold Test Sample Contents Determination Laboratory Report

The Mold Test Laboratory Report outlined below is typically 6-15 pages in length depending on the number of samples submitted and the variation in content of each sample.

The report contains complete detail of laboratory lab findings, a conclusion regarding the extent to which the samples detected or failed to detect presence or absence of an environmental problem, and if a problem was detected, the report includes details about the allergenicity, toxicity, or pathogenicity of the particles found. - © Copyright 2017 Daniel Friedman

Our mold test sample lab report is shown on this web page, just below. Separately, and offered as an on-site building diagnosis service, our diagnostic on-site building environmental hazard or mold inspection report includes our site findings, lab test results, advice for corrective measures, and other detailed advice.

That extensive report described at Mold Investigation and Mold Test Lab Reports. We also provide non-diagnostic non-invasive mold screening inspections and tests for real estate transactions and post-mold remediation (cleanup) project onsite inspection and clearance test reports. Other professional services include odor source detection, gas testing, and diagnostic inspections of overall building condition for building owners or buyers.

Fungal Spore/Allergen Lab Determination Report

Laboratory: Director Daniel Friedman
Laboratory: American Home Service Company
American Industrial Hygiene Association AHIA #149982- American Society of Home Inspectors, Certified Member #0057
Pan American Aerobiology Association - International Aerobiology Association - American Phytopathological Association
Certified Environmental Inspector CEI - Certified Testing Specialist CTS - Certified Environmental Specialist CTS - EAA
Mycological Society of America - NPMA #110947 - ICBO #22178-0 - BOCA-Certified
Certified Massachusetts Title V System Inspector, Massachusetts Department of Environmental Protection

Report Date:

4/15/2006 -- ©


Paul R. Namewitheld
Building Inspection Services, Inc.
321 Upper Road Drive
Kona Howlie, Maui HI 96790-8054

Project ID: 060415XXM1DJF
Submitted by: Paul R. Namewitheld
Sampling method: Adhesive Tape

Sampling location: 99 Babmooshoot Road, Kona Howlie, Maui Hawaii - building is located " in a gully surrounded by lush vegetation" with "recent weather conditions over the past 6 weeks have been - an above average amount of rainfall - island wide.

Description: Kitchen area wood plank wall adjacent to propane range. Rural cottage/shack in wet area, RH 58% 78 degF, post and pier foundation, interior open to outdoor conditions (screens only), building in gully surrounded by vegetation. Visible mold-suspect material on 10 sq.ft. in living room on North wall. Building was empty of furnishings at time of inspection. Wall cavities inspected at four test openings, no visible mold, not sampled.

Complaints cited: Tenant experienced a "respiratory episode" and was taken to hospital. Tenant told by a third party that she had Stachybotrys in her home. Tenant says cannot enter the building without becoming sick. Tenant's father is an attorney, threats of litigation may pertain.

Date Sampled: 4/5/06 4:00 PM
Date received by lab: 4/15/06
Date determination completed: 4/15/06
Sample Examination: at 720x-dry by Daniel Friedman, sample prepared in Acid Fuchsin/Lacto phenol cotton blue/KOH/Lactic Acid/or Triacetin with phenol

Sample # Determination
. (numbers, if present, indicate microphotographs of actual sample)
(Fungal spore names are italicized - Genera species)
-001Significant/dominant spores/particles: Aspergillus sp. conidiophores and fungal spores consistent with active fungal growth; A. versicolor present in the sample est. 25% of total mold.
"Significant/dominant, Present, and Incidental" particle levels are defined at the end of the report. Other spores/particles: - not reported unless specific details (such as unexpected spore chains or sample recurrence) appear to warrant.

[Signature] Daniel Friedman, AIHA#149982, ASHI#00577

Determination of genus/species and description completed by: Daniel Friedman, aerobiologist, PAAA/IAAA/AIHA member . These samples were examined in our laboratory using appropriate chemical/stain preparations and a light microscope at magnifications up to 1920X. Genera/species identifications were made based on experience, education, reference texts, and comparison with known samples. Credentials & experience are at

Significance of Findings: Information about the mold test sample contents

Aspergillus sp."-especially A. fumigatus, is one of the few genera of opportunistic pathogens consistently associated with disease. Aspergillosis is the general term for the infection caused by any species of Aspergillus. Four leading types of Aspergillosis are colonization, allergy, disseminated infection, and toxicity.

Pulmonary colonization and allergic reactions are induced by inhalation of large numbers of conidia."-Fundamentals of Diagnostic Mycology, Fisher & Cook. Reported to be allergenic.

Members of this genus are reported to cause ear infections. Many species produce mycotoxins which may be associated with disease in humans and other animals. Toxin production is dependent on the species or a strain within a species and on the food source for the fungus. Some of these toxins have been found to be carcinogenic in animal species.

Several toxins are considered potential human carcinogens. Common cause of extrinsic asthma (immediate-type hypersensitivity: type I). Acute symptoms include edema and bronchiospasms, chronic cases may develop pulmonary emphysema. - U. Minn.

Aspergillus versicolor: Conidia dimensions 2-3.5 microns. It is commonly found in soil, hay. cotton and dairy products, It can produce a mycotoxin sterigmatocystin and cyclopiaxonic acid. These toxins can cause diarrhea and upset stomach. It is reported to be a kidney and liver carcinogen. This species is only occasionally pathogenic- U. Minn.

General comments about your samples and your field notes: these opinions (written before I examined your tape sample in order to avoid any bias in our comments) are offered as technical background since I have not personally inspected the building you describe.

[items 1-4 deleted for privacy]

5. Use of cultures as building screens for the presence or absence problematic mold is unreliable - only 10% of all molds of any genera will grow on any culture under any circumstances, so a mold culture screening test for mold is 90% wrong at the outset. More so if one considers that certain molds that can be grown in culture only respond to specific culture media. Even if a mold is grown on a culture, given these constraints one cannot reliably infer that the mold grown is the problem material in a building.

Therefore no screening test by air or culture is an adequate substitute for nor superior to the value of a careful visual inspection by an experienced inspector who knows where mold is likely to grow and what it looks like on or in building surfaces and cavities.

6. Stachybotrys chartarum or other Stachybotrys species can be found, at least at small amounts, in most older buildings since it is common to find this mold on drywall in areas subject to water, such as behind floor trim in a bathroom. However no qualified expert would assert the presence or absence of a mold problem in a building without performing a thorough visual inspection of the property.

Therefore the theoretical diagnosis by a third party who asserted that this building has a Stachybotrys problem is nonsense. Finally, despite media attention to this mold, it is not normally an airborne spore and becomes airborne in quantity only if it is mechanically disturbed such as during demolition in a building.

7. Further investigation: The comprehensive visual inspection (already completed) is the most-critical investigation step to be performed in this matter. Based on your field notes, if you are suspicious of a history of leaks into building cavities which might produce a hidden mold or allergen reservoir, you might consider these additional steps:

  1. a screen of settled building dust (tape sample)
  2. an inspection for visible mold on the cavity side of drywall or paneling in most-suspect areas of prior leaks into walls or ceilings
  3. an inspection of suspect building cavities and possible vacuum samples of building insulation if fiberglass insulation is present in wall or ceiling cavities and in particular, if that material is suspected of having been wet from leaks of any kind.

Notes: Please see the web link references on the next page for added depth of information; For mail-in samples to a lab of your choice you would normally use their own chain of custody form but you are welcome to use and copy this CHAIN OF CUSTODY FORM for ENVIRONMENTAL SAMPLES and this


What Should be Done About Mold Found in the Samples

What should be done about mold identified in the samples? This report provides a summary of information at hand for mold or particle types identified in the samples.

If the mold test screening samples contain problematic mold, the mold should be removed. If large areas of problematic mold are present professional mold remediation is needed. Occupants who have health concerns or specific complaints should check with their physician for more advice. Additional mold and allergen health and cleanup guidance:

See MOLD ACTION GUIDE: What to do about mold, mildew, and other indoor allergens

WHEN to HIRE a PROFESSIONAL to inspect or clean-up mold

Unless the sample collection was combined with an expert inspection of the building, one cannot be certain of the extent of mold or other particle contamination in a building.

Similarly, without an expert inspection one cannot determine if a sample accurately represents all of the molds present in the building. Mold Spores-General: It is absolutely expected to find mold in air and surface samples.

Mold spores are allergens found outdoors and inside; there is no seasonal pattern to indoor molds; mold growth is related to moisture levels, temperature, and other conditions. Mold growing anywhere in the building is likely to be distributed by the air circulation, more so if the building uses hot-air heat.

The presence of incidental occurrences (one or two deselected in a sample trace) of problematic mold spores is not by itself significant as such spores could have entered with outdoor air.

However if we find recurrent presentations of problematic spores in multiple samples, particularly if the problematic spore appears to be the same species as that which was to have been cleaned and removed during remediation, and if it regularly appears in chains or clusters, additional cleanup may be in order.

The presence of mold spores in chains would suggest that there is some active mold growth in this building. These chains are so fragile that if mold were only entering from outdoors it is more likely that I would only see single spores or very small fragments.

Extensive mold contamination in buildings as well as some individual mold species have been associated with health risk to children and adults, particularly those with forms of respiratory illness such as asthma or those who may have compromised immune systems or may be otherwise at risk. A very wide range of complaints are often expressed by occupants in buildings.

These complaints might be caused-by or aggravated-by mold or other building contaminants. Any environment where extensive allergenic, toxic, or pathogenic mold/fungus is found is a potential health hazard and should be remediated.

Qualified experts who will have their own advice should handle remediation of large areas. New York State and other authorities have described remediation procedures and have identified situations where cleanup may be done by the building owner/occupant.

More information is at Where chronic health concerns are present, it is essential that building occupants consult their physician for diagnosis and advice. Where complaints persist, additional building investigation is appropriate.

Significant/Dominant Particle Levels - what does this mean in a mold test lab report?

"Significant/dominant" means that these particles were present at significant levels in the sample and/or these particles were so frequent that they were the predominant particle found, typically at least 50% of the total fungal concentration observed. Particles listed in this category are likely to be of significance to occupants in the building.

Where the particle is a mold genera or species capable of growing indoors a finding at this level makes it likely that there is one (or more) mold reservoir or mold colony in the building. When the significant/dominant particle(s) present is/are allergenic or toxic mold or an allergen, building investigation to find and clean/remove the problem source is needed.

Present Particle Levels - what does this mean in a mold test lab report?

"Present" means that these are other spores (other than the category just named above) were frequently present in the sample, typically comprising 20% to 50% of the total fungal concentration observed. They are less likely to be of significance to occupants of the building except when particles named are

1. particularly allergenic or toxic

2. are not commonly found in outdoor air or

3. of other technical significance, such as the presence of Pen/Asp spore chains.

The presence of individual or a few spores which may be toxic or allergenic is not normally itself a cause for alarm; however if the building has a history of leaks, water entry, or other hidden moisture problems, the presence of even a few toxic or allergenic spores which are not often found in outdoor air samples may indicate a hidden problem.

In these cases further investigation is in order to determine if there is a significant presence elsewhere in the building than from where this sample was taken.

Incidental Particles - what does this mean in a mold test lab report?

"Incidental" means that I found only occasional, or low-levels of fungal spores in the sample provided, typically less than 20% of the total fungal concentration observed, or below the level I usually find in indoor air samples in buildings where there has been a history of leaks, flooding, or known mold contamination.

I do not normally report particles in this category except as a point of technical/professional interest. This is a positive description of the quality of indoor air insofar as fungal spores are concerned, but one cannot unequivocally conclude that there is no possible health hazard present because:

1. individual exposure, sensitivity, and health status vary widely;

2. even a zero count does not mean a particle is not present in the building. It means only that that particle was not in the sample provided. A more careful , expert look at the building may disclose particles that an occupant was unable to recognize and thus did not send to the laboratory for determination.

Occasional occurrences of certain mold in samples could indicate a hidden or un-noticed mold problem in the building other than at the spot from which the sample was collected, particularly if the sample was collected by someone who is not expert at building science, indoor air quality, mycology, and related disciplines. Occupant indoor air or environment-related complaints or a building history of leaks would suggest that additional investigation is in order.

Sampling versus human exposure - Interpreting a mold test lab report

"Human allergen exposure differs in that an allergic individual functions not unlike a mobile air sampler in that he moves from site to site throughout the sequence of daily behavior, sampling the various environments s/he passes through.

In this respect the human aeroallergen exposure is the sum total of all the various environments passed through in a given period of time, whereas the air sampler exposure is limited to what occurs in a single environment during the same time interval."

Therefore, the samples collected at a site attempt to describe that single environment whereas a human, operating during the same time interval, will be sampling a variety of environments unless s/he is sedentary.

Mold exposure standards give a wide range of mold hazard criteria

Given these complex variables, and adding the significant variation in individual fungal spore size and probable health effects, absolute spore counts, whether viable in culture or non-viable in air or surface dust, may be useful but by themselves they are not reliable as indicators of actual human exposure in buildings where so many variables pertain.

To avoid costly inappropriate mold remediation, a quantitative "exposure standard" would have to take into account not only the wide range of individual vulnerability and exposure, but also the wide range of risk among every genera, species, and strains of mold which might be found in buildings. In many cases necessary research has not been performed.

Mold Report Terms & Definitions: how to read your mold lab report

Conidiophore: the component of a fungus which produces fungal spores.

A conidiogenous cell, or a fertile fungal cell which is specialized for the production of conidia (fungal spores). [paraphrased] - Illustrated Dictionary of Mycology, Ulloa and Hanlin. Finding conidiophores in an indoor sample is very strong evidence of an actual growing (or previously growing) fungal colony in the building.

Chlamydospores: are thick-walled resistant spores which develop to permit a fungal species to survive in a dormant state, typically waiting for more favorable conditions for growth. They are an indication of conditions previously favorable to fungal growth, and can produce future fungal activity. -- Illustrated Dictionary of Mycology, Ulloa & Hanlin, American Phytopathological Society, 2002.

Debris at excessive levels: this comment means that the sample contained excessive levels of particle debris.

When a sample collects to much debris important particles may be obscured in the debris. If it was an air or vacuum sample, high levels of debris can also cause important particles, particularly small spores such as Penicillium sp. or Aspergillus sp. to fail to adhere to the collection media. Both of these factors tend to make any estimate of the levels of spores or problem particles lower than actual in samples containing excessive levels of debris.

Genera (genus-singular): one of the principal ranks in the naming structure of organisms, this is the first part of the standard two-part species name genera species, for example Aspergillus niger.

A given genera e.g. Aspergillus, may be made up of many species members, and individual species may vary considerably in their importance to human health.

Species - (abbreviated sp.) - the lowest principal rank in the nomenclatural hierarchy [for living organisms], consisting of two elements (a binominal): a generic name ["family"] and a species epithet [specific individual member in the family. A genera such as Aspergillus may have more than 100 species, each with different potential medical and other effects.

Finally, the potential medical effects of an individual species may themselves vary depending on growth conditions such as choice of nutrient substrate, stage in sexual development of the organism, and other factors.] - taken in part from Dictionary of the Fungi, 9th ed., Kirk, et als. [annotations by DJF].

In some instances the contents of an indoor sample (air, dust, surface, etc) may contain particles which permit determination of the mold genera, but not the species. In this case we report the finding name as "genera sp." such as Aspergillus sp. rather than the more-detailed example "Aspergillus niger." Where appropriate additional work can often be ordered for such samples in order to determine the individual species as well.

Hyphal fragments or mycelia are components of fungal growth (similar to the roots and branches of a tree); it is common to find small hyphal fragments in outdoor air and possibly in indoor dust. But their presence in indoor air samples, if in quantity or in large segments, suggests an active fungal colony in the building.

Their presence in a surface sample in quantity or in large segments indicates that active fungal growth is present or nearby, or that fungal material has been disturbed in the building. May be allergenic. -DF

Mitospores - this is an artificial collection of a large group of fungi which is used by aerobiologists to refer to members of the deuteromycete class of asexual fungi which could not be identified to genera/species in the particular sample.

Many of these have been related to the ascomycetes or basidiomycetes groups. If a spore is recognizable as a specific genera or genera/species, particularly one which is already known to be problematic in indoor air it will be so-named and will not be reported in this group.

Spore, conidia, or "fungal spore," "a small unit of propagation, ™ capable of giving rise to a new individual.

A spore functions like a seed. ™ Spores can be spread by air, water, insects, or other animals. Illustrated Dictionary of Mycology, Ulloa and Hanlin [paraphrased by DF]. In buildings airborne spores are the ones likely to be of greatest risk to humans, although certain other spores which are not intended to be spread in air can be infectious if placed directly in an eye, an open cut, or on other sensitive tissues. -DF

What should you watch out for in reading a report from a mold testing lab

What about inaccurate, misleading reports? These defects can be quite dangerous: if a significant quantity of toxic material is present in an environment and in the samples collected, it ought to appear in the report. At the same time, a report which "protects" the investigator or laboratory by too-broad warnings risks wasting the client's time and money on a wild goose chase.

A good mold test lab report should identify dominant and significant levels of particles which are found present in air, surface, vacuum, or other samples. Where the laboratory is unable to "speciate" the genera it should so indicate.

Sometimes even the presence of a few spores can be significant if they are highly toxic, as they might indicate that a problem material is present or growing somewhere in the building.

But a distinction should be made between what is obviously significant by visual inspection (or if necessary by actual quantitative measurement if it was an air sample), and what was found as present but not necessarily significant.

A vague report might, for example, identify a major and common genera like "Cladosporium" by indicating that "Cladosporium sp." was found.

Because Cladosporium is perhaps the most common mold genera, and because it's a pretty big family with perhaps 40 or more members or sub species, and because perhaps one of those members or species is toxic, a hasty lab might protect itself by an asterisked note indicating "*

Some members of this genera are toxic." Further, some species are usually found in and associated with outdoor air; others are quite common indoors. This distinction might be a clue about the building condition and its air quality.

Without actually identifying the presence of a dangerous species, would it be appropriate to launch a very costly remediation program? Maybe not. To be fair, depending on the sample quality, condition, and content, it is not always possible to determine species by visual inspection.

What inspection methods and testing techniques form the basis of your indoor air/mold investigation report? Mold cultures are unreliable for overall characterization of fungal contamination of indoor air. Home test kits, settlement plates, samplers which collect spores onto petri dishes, and sterile swabs all have a place in the arsenal of tools but not for overall building characterization.

Mold Testing Laboratory qualifications

We wouldn't expect an aerobiology or "mold test lab" to operate without someone at hand who actually has some appropriate knowledge and experience.

But watch out for laboratories that are over-worked, processing perhaps thousands of samples monthly with a too-small or under-trained staff. The fact that a laboratory has some certification does not assure you that the "certification" is pertinent to the work being performed in your behalf, nor that the individual actually doing the work is properly trained.

In one class I attended a mold test lab supervisor showed me the "cheat sheet" she provides to her afternoon high-school aged employees who are "trained" to look through the microscope for one of the eight common mold species whose photograph appears on a colored card

. An under-trained lab technician may be tempted to stop examining a sample as soon as s/he finds one of the "important eight" on the card.

In a similar case we found a lab which over-reported the presence of Stachybotrys chartarum which was less important as an airborne presence in that particular building than a very large colony of Aspergillus niger .

Why was this error occurring? Because Stachybotrys chartarum is a comparatively large black spore which is easily recognized in a sample while the Aspergillus niger spores are tiny and nearly colorless, requiring more careful and patient microscope work to recognize.

Really? But wait a minute! One can hardly expect a laboratory to diagnose a building based simply on a few samples collected by someone else, possibly by someone with no proper experience.

The best a mold test lab can do is tell you what's in the sample collected, not whether the sample represents the building and not whether the sample captured the most important problem in the building.

How can you be more confident? Inspect the building with knowledge and care. Collect historical and occupant data. Then perform good lab work and lab interpretation based on the site data.

Can you understand your toxic mold test lab report? Finally, you should be able to read and understand your lab report. If you paid a field investigator to examine your building you should be able to ask that person for additional advice concerning the lab results, and you should also be able to ask the lab director questions if the report is not clear.

Investigators who disclaim any responsibility to you, saying "ask the lab," and laboratories who say "we just process the sample, ask the investigator" are not being as helpful as they should.

For a discussion of valid and not very valid site inspection or site investigation reports for mold see MOLD INVESTIGATION REPORTS


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