What this video covers
The clip explains why cheap settle-plate test kits tell you very little.
A gravity plate left open will always collect spores, because spores are present in every building and in outdoor air. A positive result therefore says almost nothing, since the same test run in a healthy house returns the same answer.
The takeaway
A test that cannot produce a negative is not a test. What is useful is a comparison against outdoor levels, which is what proper air sampling provides and a settle plate does not.
Read the full written guide: Mold Testing Guide.