I've just done a test, sensitivity says it's 20miu.
I left it for a minute or so and saw this line come up, it was still there when the test had settled so I removed the casing to have a closer look at it. Then there was obviously a line that looks a bit smudgy but the same thickness. But I just left it on the side and it's disappeared after about 5 mins.... I'll have to test again I know but does this just look like an invalid test?? I know it's technically invalid now as the casing is off but it was there before I removed it... thanks x AF is due in 3 days...