US Health Tests

I'm on probation right now and If you haven't read my other thread heres a little bit about my body type. I'm 5"8 and about 128 pounds. I smoked from march 25th till april 3rd about 5 or 6 grams worth. I have been clean since and I have to go to my po thursday. I might get tested and I might not. I'll be 15 days clean including the day of my test. Anyways I tested my self with a few home tests from wall greens. Two times with the At Home Tests and once with the First Check tests. The first time with the at home test I failed with a very faint line that couldn't be photographed. The next one I passed with a very faint line, but you could barely see it in a picture. The First check test I Passed with a pretty decent line. You can see a pic in my other post. Anyways I bought these thc strip tests online from amazon. They aren't even FDA approved as far as i can see. I've read the instructions. The company is called US Health Tests and they are these really flimzy little pieces of plastic. Well, I tested my self three times with these today and failed all three. So, i decided to go get another test from CVS. I got a first Check and I passed it with a line that can be photographed. Then I used the same urine and stuck one of the US strips in the same urine like 2 mins later and not even a control line came up. I'm starting to wonder if these little tests are crap. I don't know what to believe. I had a buddy who has never smoked test himself and it came up negative with the US tests. Has anyone else had problems with these also. Which one should i beleive? Sorry about my grammer also.

Anybody know anything about this company?

Never used US Health tests before. They have the standard 50ng cutoff for thc. Don't know why you would be having problems with them unless they are really shitty quality.

Yea, I think they use the 50 gc cut off level, but they look very cheaply made. I can't find anything about them on the internet and the instructions look like they've been photocopied. Here is some pics of one of them.http://img255.imageshack.us/img255/3...102akm9.th.jpg
http://img409.imageshack.us/img409/9...2102ls4.th.jpg