Why DIY Mold Test Kits Are a Bad Idea

9/25/2019 (Permalink)

The most important part of a mold inspection is the inspection, not the mold samples.
Mold samples can be misleading, are sometimes incorrect with both false positive and false negative results occurring, and can only be accurately interpreted in conjunction with a well thought out sampling plan and visual inspection. The visual inspection requires an understanding of building construction, water sources, and other factors that may not be apparent to many people, such as condensation occurring in a poorly ventilated attic, poor drainage on the exterior of a building, or cracks in the foundation.

Consumer Reports rates home mold test kits "Not Recommended"

In 2006, Consumer Reports evaluated four different types of home mold testing kits and rated all of them "Not Recommended," including typical comments like this one for the Pro-Lab MO109 mold test kit: "In some samples, the vials with media leaked over entire kit. In one, an unopened kit was moldy. No expiration dates on the kit; old media could affect the accuracy and reliability of the results. Label claims that kit can identify toxic mold, but the report the lab sends can't tell you this. One unused plate came back positive for mold growth, indicating contamination at some point; not very reassuring for post remediation use."

Mold test kits do not provide meaningful answers.

The primary issue with these kits is they essentially only test for the presence of mold in the home. The mold testing kits that we are aware of are simply "gravity" or "settling" plates which consists of putting an open Petri dish in the home for some period of time. This is about as useful as setting out a plate of fruit and finding out whether mold will grow on them. Given enough time, of course it will! If you leave moist food on the kitchen counter for a few weeks, no one is surprised when mold forms on that food, and finding mold on that food does not mean that the home has a mold problem.

It's important to understand that mold is ubiquitous – it's everywhere. ALL homes have mold in them. Mold is present in homes, buildings, and the outside air. Mold spores are in the air, on surfaces, on the furniture... all over the place. If you open a Petri dish and take a sample, it is likely that you will get mold growing on the Petri dish. That's not helpful information!

The Bottom Line: These mold test kits generate money for the companies selling them and generally, just cause fear in the person taking the sample with no real added value. Further, the most important part of a mold inspection is not the mold sample, but rather the inspection of the building for sources of moisture and evidence of mold. Often, mold testing is not even necessary.

Source: http://www.moldreport.com/home_mold_testing_kits.html