Hi, I did 2 Tesco pregnancy tests the other day, and both came up with thin blue lines where the positive would be. I'm confused because I thought evap lines are supposed to have no colour? But these are obvious blue lines. I saw a post from years ago where a lady had the exact same thing on these Tesco tests and turned out she was 5 weeks pregnant! Has anyone else experienced this and been pregnant? Just to add - the thin lines appeared within the time frame of the result.