If it's surface mold, where are they finding it? Bathrooms are a common location, esp around plumbing and high on walls.

Thanks -

That's just it - they are testing the "air" but there's nothing to be seen anywhere.

It's perfectly pristine and clean everywhere and never any issues with leaks etc. Nothing on any surface anywhere.

How are the tests conducted? How are the samples and sample equipment handled? Are you certain the contamination isn't in the equipment? Conduct your own test and ensure protocols are correct.

Is your air possibly more humid so there would be an above average reading potentially due to that?

Supposedly the guys finding this are pros -

They are retesting today. If it comes back + again the sale of our house is dead for sure. :-/

We don't live in a humid climate.

I was just hoping to find out what they do in cases where it's impossible to actually see any evidence of mold. Maybe the guy who tests again today will know.

Not humid climate, but rather the inside of your house being more humid than average in your area.

After some specialists came to test - 30% humidity inside - and no signs in the house anywhere - they were shocked! BUT - they might have found a source - loose HVAC parts in the crawl space under the house causing condensation and then blowing up into the house.

They will have to fix that, clean up down there and then ionize the air in the house and HEPA Vac - also possibly wipe down the flat surfaces with some kind of stuff to mitigate. Hopefully this is the cause and solution in one simple pass. Just hope it's not too expensive to treat as they say insurance probably won't touch it since it's not caused by a "sudden" event.