I don't usually use blue dye cuz I've heard of bad evaps but my fiance bought them. If there's a fairly light thin line just off centre, is that an evap? I tried to take a pic but it doesn't really show cuz it's so faint. I've used these tests once before and both came out what I thought was positive but I was actually pregnant so I guess evaps. This ones a bit more centre then the last one but still pretty thin.