Thanks, but what do you make of two separate manufacturers strips with opposite results? One with two solid lines and the other with only one line. Both tests done at the same time using the same sample. And on one strip you almost need to use your imagination or hold it at certain angles to see it? Are the comments I've read that say " a very faint line demonstrates thc levels at or near the cutoff? Is this totally bogus?. If I was the lab I would question such a faint line and find it hard not to find it positive when it is so hard to see. I get the feeling that I have one set of strip tests that don't have sufficient color on the test line. Your thoughts?