A word regarding Petri dish test kits sold at hardware stores, supermarkets and etc:
These kits are set up per the manufacturer's instructions (per web site 2/5/2010):: "Remove the lid of the Petri dish and pour the mold medium into the dish bottom. Replace the lid and swirl gently until the bottom is completely covered. Allow to harden for 1 hour on a level surface."
The web site states in regards to the test kit limitations (2/5/2010): “Note: "All sampling methodologies are subject to the occurrence of false negative and false positive results."
It is almost guaranteed that you will have mold growth in your dish ("false positive"). All homes have molds inside of them. The Petri dish will collect the natural molds inside of your home and the user will incorrectly assume that a elevated mold condition exists when they see ugly mold growths in the Petri Dish, thereby making the tests completely useless and even detrimental in regards to determining if a location has an elevated mold condition.
Even if the product was set up according to IAQ baseline standards (which are not suggested by the manufacturer's instructions at the time of this writing) the baseline sample would have a disproportionate advantage of collecting spores due to natural environmental currents, once again rendering the kits useless. This does not take into account that the user has a 50/50 chance of erroneously placing the baseline sample in a position where some molds would be adversely affected and will not grow making it seem as if there is an elevated mold problem in comparison tests. The manufacturer's directions do not suggest a baseline test in the first place. Secondly, they do not specify a location that will not be affected by environmental factors. Third, these tests are of little use to IAQ professionals since our aim is to find the amplification of growth on the inside and not just merely what molds are there.
At least the Petri Dish manufacturers were up front about the limitations (in a half truth tone).
Unsuspecting homeowners will see the see the ugly mold growths in the Dish and/or laboratory results (if purchased) and see several molds found within the home, assume that they have a mold problem and proceed in calling a mold remediation company who may or may not inform them that the test that they had performed is completely useless (at least to you, the building owner). This could potentially (its a 50/50 shot) cost thousands of dollars when no elevated mold condition ever existed.
Don't waste your money!
Do It Yourself (DIY) Toxic & Black Mold DNA self testing kits only identify limited molds classified as "toxic" by the EPA. Molds that are harmful and not harmful are not included in the analysis. If you have an allergic reaction to a harmful or even non-harmful mold, the analysis will not make mention of those particular types of molds leaving you wondering and eventually having to properly retest the area again. Please make note that determinations of toxicity in molds is an ongoing process. Science has not yet identified thousands of molds, in regards to human health effects and is consistently updating data. A "DNA" sample is obtained by collecting dust from virtually "anywhere in the house". Professional testers now collect a swab sample from a specific area that has a discoloration resembling mold(s), moisture laden areas determined by protimeter analysis and/or insect farmed areas and etc. The "DNA" self test kit takes this dust sample from anywhere and if any elevated molds are found, implies that those molds are constant throughout the entire home without any regard to where or why the mold originated from. False results will be obtained using this method when molds naturally fall to the lower floors of a building. This is why it is so important to have a mold inspection performed on the house. You may be able to determine that the house has a few types of mold(s) in a particular place in the house by using the "DNA" kit test but, you will not know where or how the mold has formed without professional evaluation. Cleaning the mold will have little effect if the causes for the molds are not identified.
American Relative Moldiness Index (ARMI) - "This panel {only} includes 13 mold species, including species that are known to thrive in water damaged homes and species of molds that are found in all homes, with or without water damage. Each species and group of species is enumerated from DNA extracted from dust samples taken from both the living and sleeping quarters of the home. Concentrations of each of the 13 molds are used to derive an “ARMI score” that rates the moldiness of each sample against those tested by the US-EPA. These values range from approximately –10 (low moldiness) to 20 (high moldiness)."
There are thousands of known species of molds, which include opportunistic pathogens, saprotrophs, aquatic species, and thermophiles. The ARMI test only tests for 13 species that were identified by the EPA to be geographically specific to the region (Ohio) tested. Once again, a determination of toxicity in molds is an ongoing process. Science has not yet identified thousands of molds in regards to human health affects and is consistently updating their data. By limiting the amount of molds that can be analyzed, not only by number but by geographically specific data which is also subject to the frailties of misinterpretations or incomplete information, this puts you in the position of having to properly retest the area if your mold issues are not addressed by the limited ARMI testing protocol. An ARMI sample is obtained by collecting dust from virtually anywhere in the house.
Professional mold testers now (and have for many years) collect a swab sample from a specific area that has a discoloration resembling mold(s), moisture laden areas determined by protimeter analysis and/or insect farmed areas and etc.. The ARMI takes this dust sample and if any elevated molds are found, implies that those molds are constant throughout the entire home without any regard to where or why the mold originated from. False results will be obtained using this method when molds naturally fall to the lower floors of a building. This is why it is so important to have a mold inspection performed on the house. You may be able to determine (limited to 13) that the house has mold(s) in a particular place in the house by using the ARMI test but, you will not know why the mold has formed without professional evaluation. Cleaning the mold will have little effect if the causes for the molds are not identified. But, the EPA has come up with a test that can analysis 36 molds. Unfortunately the same applies to this type of testing but to a somewhat lesser extent.
"The "new standard in mold testing". The Environmental Relative Moldiness Index (ERMI) is a Quantitative, Real-Time Polymerase Chain Reaction (QPCR) panel of testing for indoor molds that was developed by the United States Environmental Protection Agency (US-EPA). This panel includes 26 mold species and groups of species that are known to thrive in water damaged homes. This panel also includes 10 species and groups of species of molds that are found in all homes, with or without water damage."
The EPA has stated ""All molds have the potential to cause health effects. Molds can produce allergens that can trigger allergic reactions or even asthma attacks in people allergic to mold. Others are known to produce potent toxins and/or irritants. Potential health concerns are an important reason." The U.S. EPA, March, 2001." Why is there only 36 molds tested if "all molds have the potential to cause health effects", you may ask? Sounds as if the insurance companies are going to love the new EPA testing procedures.
Continuing with the ERMI test description: "Each species and group of species is enumerated from DNA extracted from dust samples taken from both the living and sleeping quarters of the home. Concentrations of each of the 36 molds are used to derive an “ERMI score” that rates the moldiness of each sample against those tested by the US-EPA. These values range from approximately –10 (low moldiness) to 20 (high moldiness).".
This test is considerably higher in cost and is gathered by vacuuming portions of the carpet for 5 minutes. One of the problems with this test is, it is all scientific theory with no practical field experience. If one were to take a carpet sample using the recommended testing method, this test does not take into account that many carpets are improperly installed without a sufficient moisture barrier. This in turn will grow mold on the carpet from the moisture in the concrete floor. Not only will the carpet grow mold(s) but also the padding underneath. So when a vacuum sample is taken from the carpet, the mold(s) from the padding that are not regularly introduced into the air, will come up (if it is one of 36) in the test. When it does, and the result applied as if the mold is present throughout the entire house giving inaccurate readings once again. Unfortunately again, the same drawbacks of the ARMI test apply here as well.
In summary:
All of the DNA tests above are extremely limited (although touted as precise) in their detection.
All of the DNA tests assume a common sensitivity to molds from all peoples.
Some of the DNA test results are concluded by the limited data (and therefore limited results) the EPA has gathered per geographical region.
All of the DNA tests are subject to questionable methodologies in regards to gathering the sample(s).
All DNA tests are relatively new in regards to mold testing.
All of the DNA tests assume that the consumer will know the right test to perform (although the consumer will usually choose the least expensive test).
All of the DNA tests take surface samples and imply that the results are airborne through extended areas where the testing was not performed.
The Petri Dish method does not take into account exterior mold levels and is useless in detecting elevated mold levels inside of your home.
Air O Cell Air Sampling is still considered the established method of airborne mold contaminants.
Ohio Mold Testing Inspections - Test Kits Do It Yourself DIY
Ohio Mold testing & inspections services:
House To Home Enterprises LLC - 3491 State Route 131 - Fayetteville OH. 45118