Why don’t we sample from the bathroom or kitchen?

The reason we give that guideline is that bathrooms and kitchens often have elevated levels of humidity (and thus also mold), and we want your results to be as representative of the entire home you live in as possible. Sometimes including those rooms can skew the results a little higher, and any dust from those rooms will also float freely into the rest of the home, so mold present there will still be caught in the test overall. If you have open-plan spaces, that is no problem, just avoid the kitchen surfaces directly.