Mold testing is quite controversial.  There are valid reasons for the controversy.   There are valid reasons to employ the use of testing.    Testing should be performed in order to support/confirm a hypothesis that was derived from a thorough inspection.     However, this is often not what is occurring in the industry.  

Mold testing is controversial because there are many individuals that conduct mold testing that do not have knowledge to interpret the results.     Mold testing is also controversial due to the limitations of each type of test.  Those that only offer one type of test can not possibly be offering the most appropriate test all of the time.   

If testing is to be conducted, there should be a hypothesis that the results would help confirm.   There should be strategic location(s) selected for the test and an idea of the interpretation of the results should be determined prior to the test being conducted.   In most cases, this is not commonly happening.   Home inspectors, mold remediation companies, and other mold testers pick a “central location” to conduct a mold spore trap analysis in which the laboratory provides the results and interpretation.    The laboratory interprets results without knowing anything about the environment; whereas the person conducting the testing should be the one qualified to interpret the results.     Picking a “central location” is typically one of the least effective places to evaluate a space overall.   These are just a few reasons that mold testing has a less than favorable reputation.   

There are many methodologies to test for mold in an indoor environment.    All testing has some limitations within each method and testing is also limited due to financial constraints and/or the desire for quick results.   Below is a quick overview of testing options.    

Direct examination of mold.   Using a “tape lift”, swab, or “bulk” material, an analysis can identify the presence of mold.    This method is quick, accurate*, and relatively inexpensive but provides no information on the impact to indoor air quality.  *The accuracy would depend on picking an appropriate sample.   This is often used in real estate transactions to “prove” to a materially interested party if something is confirmed to be mold.   Typical costs are $90-$130 per sample.   If the type of mold is desired, results are usually provided within 2 business days.   If the type isn’t important, results can be obtained the same day. 

Mold spore trap analysis is an inexpensive method with quick results that indicate the number of mold spores in the air during the time of sampling.  The “types” of molds can be identified.   Many mold species spores appear similar during evaluation and are combined as one “type” as opposed to identifying the exact species.   Mold spore trap analysis results can vary widely in the same environment due background variables, the volume of air sampled and the physical characteristics of mold spores.  Mold spore trap cannot confirm mold growth and/or active mold growth.    Additionally, mold spore trap analysis generally does not detect mold behind or in wall cavities.    Mold spore trap analysis provides results within 2 business days and typically costs $90-$130 per sample.   An outdoor sample is required as a control.   

Viable mold sampling (culture) is a method that takes longer to receive results and is more expensive than a mold spore trap analysis.   Viable mold sampling takes mold spores and allows them to grow in the laboratory to identify the species type(s) found.   This provides more evidence of actual types of molds than the spore trap analysis.   Viable mold sampling was historically the traditional way to determine species of mold present and determine if mold spores were viable.   These tests are seldom used anymore as knowing the information provided from the sampling is not valuable enough to wait for the time it takes to receive results (typically 1-2 weeks).

Mold VOC testing provides relativity quick results to determine the presence of active mold growth.  VOC testing is best used to determine if there is an active but hidden mold problem prior to using destructive means.    VOC testing is limited in that no types of molds can be identified, and no location of any hidden mold.  However, the sensitivity of the test provides accurate information on active mold growth.   One test can cover up to 2,000 ft² and typically costs around $400.   Typically, the cost to test is often less than the cost to replace drywall.  Results are typically available in 3-4 business days. 

Mold testing using DNA to identify the presence and types of molds results usually take longer.   The results are more accurate to identify species of molds and to some extent, the “quantity.”   The ERMI test, developed by the US EPA, but not recommended for commercial use,  uses dust samples to report on common (but not all) molds found indoors.   The results are compared to an index.   The EMMA test also uses DNA to determine the presence of common molds.   The EMMA evaluates mold and mycotoxins. Neither test provides information to the location of the mold, the fungal “load” of the building or current active growth.   These tests typically cost $400 per sample and take approximately 2 weeks for results.  

Mold testing using biochemical analysis has existed for years but has rarely been used in residential or commercial consulting applications.   The Mycometer is the only EPA verified method for fungal analysis using an enzyme that is present in most fungi to quantify the fungal load of a building.  The Mycometer provides the quickest and most accurate results of the fungal load of a building.   The method does not determine types of mold.   The Mycometer uses active sampling, which does disturb the air, which requires PPE for use.   The costs are $100-$130 per sample and results are available same day (can be immediate if arranged)  

Indoor Air Programs offers the most appropriate mold test for each situation.   The Mycometer is the most accurate test but may not always be the most appropriate.    Once the space is evaluated, if testing is recommended, a recommendation for which test will be provided.