I’ve used hardware store “mold kits” where you tack some tape onto a surface and then send it to a service that will analyze it for you. My understanding is that these services simply look at the tape through a microscope, or apply it to a growth media that’s been prepped to “prefer” the specific types of fungus they’re looking for.

One would think there are PCR-based services that do this? That would be the gold standard for this stuff, and it could easily scale enough to become economical, but to my knowledge there are no commercial mold testers that do this.