Bests & Worsts Reviews from Amazon

Bought two tests and had them overnighted. Amazon told me it wouldn't arrive for 2-3 days. I called the company itself to check & talked to a super great guy that made sure it went out that day....Anyway, tested dust in one room. After 5 minutes, I saw nothing = negative. Directions tell you to check again in 15 minutes but not after 30. After 15 minutes there was a line only visible to me (not my husband), so we weren't sure what the answer was. (Like someone said, it's like a preganancy test. If this was a pg test, I would think it was negative but I would retake to be sure. So, that's what we are doing.) After 30 minutes there was a barely visible line but it says after 30 minutes test is invalid. Little confusing. However, we tested a drywall area that looked suspicious and clearly, almost immediately, it was positive. No question about it. We're going to do more dust tests & if they are still unclear, we're going to send off to lab. They say you get an emailed report within 5 days of receipt, & it's only $19.95 per test. It comes with postage paid envelope & all supplies needed to send in. PS. On company website, they have more advanced equipment you can rent, which is cool. So much better than spending hundrends of dollars on a guy who may or may not know anymore than you!