Not to get your hopes up,I did this. Tested a week earlier than I should, got a negative and hid it in a draw. Got a faint positive a week later (superdrug again) so rembered the test in the draw so went to compare them and there was a clear line on it! Not sure if I didnt wait long enough the first time or whether it was just an evap line. Either way I was definately pregnant! Good Luck!!!