Are you wondering about whether professional mold testing is much different than DIY mold test kits? I myself am a mold inspector and I wonder the same thing. This is why I decided to do an experiment to get to the bottom of this. I hypothesize that all DIY mold kits will grow mold because there is a baseline of mold in the air, and that professional air samples provide much more valuable info. Yes, I am technically biased because I want the answer to be that professional air samples are much better because that validates my career choice. However, I am a scientist first and I am ethical so even if I am wrong I would switch careers before I would falsify results. That being said, here is a quick summary of the results and conclusions from my experiment while I work on a full video of the experiement.
Experiment: Take a professional air sample and use a Home DIY mold test kit in the same place which has had confirmation that no water damage or mold growth exists.
Hypothesis: The home DIY Mold test kit will show mold growth indicating that there is a mold problem and the professional air sample will show low, normal mold levels indicating no mold growth.
Results: The DIY home mold test kit grew 2 types of mold but did not grow as many colonies as I anticipated. The professional air sample showed low and normal mold levels indicating no mold growth.
Conclusions: While the DIY home mold test kit showed less growth than I had expected I am still left needing more information. I don't know what types of mold are growing and I don't know whether 2 colonies are enough to believe there is a mold problem or not. It seems that it could be valuable if the results where either lots and lots of mold colonies of different types but anything but that I am left unsure if I need to be worried or not. If no mold shows up then I would find that to be strange as well because of how much mold is generally in the air at all times.
The Professional air sample showed which types of mold where in the air and how many spores were present, which, when compared to the outdoor reference sample taken shows that there is nothing causing elevated levels of mold in the indoor air. We know there is no toxic mold present and also that there is no mold growth and most likely no water damage in the area as well. The amount of information obtained by the professional air sample still heavily outweighs what we learn from the Home DIY kits.
Based on what we found I can't say that the DIY test kits are good or bad because I can't comment on their accuracy. But I can say that in my opinion we don't learn much unless the petri dish is overflowing with mold. Yet still you wouldn't know what types of mold are present which is definitely very important. If you are breathing toxic mold you want to get out of there while if it is common plant mold then it isn't as hazardous.
In the end, I think if you get a DIY mold test kit because you think their might be mold in your home and want to save some money, I think you are going to end up hiring a professional mold inspector anyway. The DIY test kit just doesn't provide enough info and the general public is not trained to know how interpret that info. I'll have a video up soon documenting the whole experiment, stay tuned!