In my personal experience I have not had any problems. I've always taken the cheap pregnancy test (usually Walmart Equate brand) and never had any problems. My sister on the other hand recently has taken 3 E.P.T tests and they all were the exact same, but none showed absolutely clear results. The horizontal line was dotted, but the vertical line was definitely there. We are pretty sure she's pregnant, but we thought that the horizontal line should be solid to reassure you that you did the test properly. She's going to get another brand of pregnancy test and then go to the dr. anyway.