So, I got a really really faint positive on a frer this morning and this afternoon I got curious so decided to use a cheap strip test, not really expecting anything. Anyway, I didn't see anything come up within a few mins and decided to leave it. Probably 10 or so mins later I decided to have another look while I was there and I noticed a really faint line which had colour. Obviously I know the test is invalid if nothing in the time scale but why would the line have colour? (Or is it irrelevant?) xxx