Sample |
Target |
Type |
Quantification |
Equipment | Air-o-cell | air | non-cultured | spores/m3 | high volume sampling pump + cassettes | Allergenco | air | non-cultured | spores/m3 | Allergenco sampler + greased slides | Andersen | air | cultured | CFU/m3 | Andersen sampler + petri dishes | Bulk(a) | bulk\dust | cultured(a) | CFU/g (b) | none | Swab(a) | bulk\dust | cultured(a) | CFU/m2 (c) | sterile swab (Q-tip or cotton ball will work) | Tape-lift | bulk\dust | non-cultured | ID only(d) | clear sticky tape (scotch, etc...) |
(a) Bulk and Swab samples can be tape-lifted for direct examination(b) Quantification of cultured Bulk sample requires that more than 1 gram of sample be provided(c) Quantification of cultured Swab sample requires that the area sampled (9 cm2, 1 square inch, etc...) be measured and provided(d) A semi-quantitative rating is provided to indicate relative quantities present if more than one type of mold is detected
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Notes: | | |
Non-cultured | - viable and non-viable spores (and other particulate) directly examined under a microscope | |
Cultured | - viable spores are grown in a petri dish for several days before identification | |
CFU | - colony forming unit |
General: Stachybotrys does not grow well in standard culture media, and direct examination is the preferred method of identification (airocell/allergenco or tape). If you are specifically testing for stachybotrys using a cultured method then Rose Bengal type media should be used (Andersen) or requested (swab or bulk). Gravity plates (commonly found in "home test kits") are not generally used by professionals Airocell & Allergenco - this is a non-cultured air sample. Results are reported in concentrations of spores per cubic meter (spores/m3). This test is referred to as a "snapshot" of the air at the exact time of sampling. Results account for both alive and dead spores as well as pollen, skin, insect parts etc. if a full profile analysis is noted. It is important to note that allergic reactions can come from dead spores and alive spores alike. In addition, the toxins that some fungal spores produce remain toxic after the spore itself has died. Normal laboratory turnaround time is 24 to 48 hours.
Interpretation of results: the general guideline to follow is that the concentration and types of spores in the inside sample should be similar to or lower than the concentration and types of spores found in the out of doors sample. The category Aspergillus / Penicillium are small (1-3 microns), round, colorless spores that may be: Gliocladium, Trichoderma, other morphologically consistent with Aspergillus / Penicillium types. A culture sample would be necessary to differentiate between them. Currently there are no dose response relationship statistics for allowable or safe levels of aeroallergens. However if spores of Aspergillus / Penicillium or Stachybotrys are found inside regardless of the concentration, further investigation to the source should be conducted and evaluated by a professional. Andersen – This is a cultured air sample grown in the laboratory on Malt Extract Media. Results are reported in concentrations of CFU’s per cubic meter (CFU/m3). Results indicate the number of viable (alive) spores in the air at the time of sampling. Analysis does not and cannot include counts for dead spores, pollen, skin, insect parts, etc. It is important to note that allergic reactions can come from dead spores as well as live spores. In addition, the toxins that some fungal spores produce remain toxic after the spore itself has died. Normal laboratory turnaround time is 5 to 10 days. Interpretation of results: the general guideline to follow is that the concentration and types of colonies found in the inside sample should be similar to or lower than the concentration and types of colonies found in the out of doors sample. Currently there are no dose response relationship statistics for allowable or safe levels of aeroallergens. Please note that Stachybotrys does not grow well on laboratory media and an absence of Stachybotrys on a culturable sample report should not rule out this type of mold. Bulk – this type of sample can either be analyzed by direct exam (see below) or by culture. The cultured sample is grown in the laboratory on Malt Extract Media. Results are reported in concentrations of colony forming units per gram of sample (CFU/g). The results of a bulk sample culture can be problematic because of the inconsistency of contamination of the material sampled. Additionally, Stachybotrys does not grow well on standard culture media, and an absence of Stachybotrys on a culturable sample report should not rule out this type of mold. Normal laboratory turnaround time is 5 to 10 days. Interpretation of results: less than 10,000 is low 10,000 to 100,000 is medium 100,000 to 1,000,000 is medium to heavy greater than 1,000,000 is heavy Direct Exams (bulk) and Tape lifts – this is a non-cultured sample. Results are reported as "detected" for each type observed. This test is primarily qualitative and should not be used if quantitative results are needed. If a direct exam results are negative, a bulk culture of the material is recommended to verify results. Spores can be down inside the material and can be missed by direct exam. Most people use this test in combination with an quantitative analysis such as Andersen or Allergenco. Normal laboratory turnaround time is 24 to 48 hours. Interpretation of results: to be used to identify the type of mold to a Genus level in most cases. Not for quantitative analysis.
EPA, OSHA, NIOSH and other occupational health related associations in the U.S. have not yet to this date established permissible exposure levels (PEL), recommended exposure limits (REL), or other limit values for aeroallergens. The general guidelines listed here represent commonly accepted interpretations and practices derived from various sources, including the American Industrial Hygiene Association and Health Canada. Please realize that the evaluation of one's specific results in terms of potential health hazards and subsequent courses of action are beyond the scope of the laboratory analysis. Links on the Consultants and Resources page provide additional guidance in this regard. Those requiring expert advisement on a particular situation should retain the services of a professional IAQ consultant. |
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