Why is this important to you? 

If your assessor fails to identify the appropriate laboratory and/or laboratory analytical method on his/her Chain Of Custody (COC), the laboratory analysis may be flaw (i.e., it may not provide for your assessment needs or the purpose of the mold sample). This is not only a waste of time and money but may lead to additional liabilities (e.g., a misdiagnosis of the area being sampled). 

Laboratory Analytical Methods:

A number of laboratory analytical methods are used to assess whether an unwanted or abnormal mold-related condition exists in a given sample. The following are most often requested of mold assessors in the United States: 

• Direct Microscopy. This is one of the most often used methods in the mold assessment industry, because it is the most taught method to mold assessors. This method visually identifies and counts the mold spores and fragments (e.g., hyphae). It does not distinguish between viable (i.e., living) and non-viable (i.e., not capable of living) mold spores nor does it identify the species of the organism ( - while it will determine the genus, e.g. Aspergillus, it will not determine the species, e.g. Aspergillus flavus -), as do other methods, but is good for the (1) confirmation of visual colonization in a given surface, (2) clarification of mold colonization where suspect in a given surface, (3) determination of the mold spore population (i.e., the types and quantity of mold spores on a given surface or in a given air-mass), (4) and other applications. Laboratory analysis is often faster than other types of analytical methods we’ll be discussing.
• Culture. This method is commonly performed to expand the spore count into a determination of which of the mold types are viable and what are their species. While this may be beneficial for those seeking to determine if a given (or group of) mold species are present in relation to a diagnosed disease, there are technical limitations to this sampling and analytical method that must be considered, including but not limited to (1) bacterial infections of the sampling medium, (2) the type of mold being sought out (as some mold spores have highly specialized growth conditions that are not mimicked by the contents of the sampling medium), (3) the type of mold being collected on the sampling medium (certain spores produce inhibitors that can prevent growth), (4) overcrowding of spores on the sampling medium, (5) desiccation effects on collected mold spores, (6) the viability period of the sought after types of mold (as some mold spores have limited viability periods).
• Polymerase Chain Reaction (PCR). This is a laboratory tool for assessing the content of mold in extracts and surface dust. It may detect the presence and relative levels of twenty-six mold species associated with water damage and ten mold species not associated with water damage but cannot (as of the date of this publication) detect all species of mold. (Consider there are over 180,000 species of mold and we’ve just discussed its ability to identify less than one hundred.) While this method may be beneficial for those seeking to determine if a given mold species is present (e.g., Histoplasma capsulatum where bird or bat droppings/infestation has been observed or an occupant has been diagnosed with Histoplasmosis), its limited ability to define the mold populations along with some governmental recommendations to limit its use in building diagnosis (e.g., the EPA doesn’t recommend ERMI be used in building diagnosis) means you should always discuss the pros and cons of its use with your mold assessor prior to its application.