5 Reasons to Stay Away from At-Home Mold Test Kits

Written by: L.E. Alexander, ESG Environmental Services Manager

Our firm regularly receives calls from homeowners who have purchased at-home mold testing kits that seemed to provide evidence of fungal growth. These kits generally contain settling plates which are simple sampling dishes with agar (a food source for mold). The homeowner is instructed to leave the plate uncovered in their home for a certain amount of time and then cover the dish and check for any growth over the next few days. Below are a few reasons why at-home mold testing kits may be a waste of your money.

  1. Some mold is a natural part of the indoor environment. If mold spores that are naturally present in your home settle on the test plate, chances are they will grow into mold colonies. That does not mean these same mold spores will grow into colony forming units on building materials or belongings in your home.
  2. One test kit is not the same as another.
    • Kits may not contain expiration dates and could therefore sit on a shelf in a warehouse for extended periods of time. All culture plates containing agar media that are used by reputable labs and testing companies must contain expiration dates and should not be used if they have gone past the listed date.
    • If mold colonies do grow on settling plates, homeowners have the option to send the kit off to a lab for an analysis. Many of these labs are not accredited to perform proper analysis of fungal samples. Any lab that claims to perform mold analysis should be accredited by the American Industrial Hygiene Association (AIHA). 
    • In order to have the sample analyzed by a lab, it must be shipped. During the shipping process, samples can be exposed to extreme temperatures and rough conditions. These shipping conditions may lead to false negative or false positive results.
  3. Settling plates only measure viable or living spores. Non-viable spores can be just as detrimental to the health of occupants. In order to accurately asses an indoor mold issue, viable and non-viable spore should be measured.
  4. Certain types of spores may not grow as readily on the agar settling plates used in the majority of home test kits. Heavier spores are more likely to land on the agar, while lighter spores may not settle at the same rate. Also, water-loving fungi such as Stachybotrys, commonly referred to as 'black mold,' are not as likely to grow on settling plates as they do not contain the optimum food source.
  5. An inspection by an experience and certified mold assessor is crucial. The EPA states that "sampling for mold should be conducted by professionals who have specific experience in designing mold sampling protocols, sampling methods, and interpreting results."
    • Indoor Environmental Professionals (IEPs) have the ability to collect samples with equipment that can measure specific airflow rates resulting in more precise lab results.
    • One at-home mold test kit is not sufficient to reveal a specific indoor air quality issues. Trained inspectors can develop a sampling rationale to include control samples from other areas of the home as well as outdoors.

Whether you are experiencing health issues or are generally concerned about the indoor air quality of your home, an at-home mold testing kit is not going to supply you with the answers you need. ESG's Council-certified environmental investigators have extensive experience evaluating indoor air quality issues and developing sampling rationales to correctly diagnose a mold issue. Visit our mold investigation page to learn more about our process.



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