HPT question

[catbus]

Why do home pregnancy tests say to not read the result after 10 minutes? I got a Tesco one today, and after about 3 minutes of waiting it said negative. Then had a peek before I was about to bin it and there is a (slightly faint) positive. What is that all about?
I do remember a similar thing happening once before, and it turned out I was pregnant. I have irregular-ish periods, so technically I am testing about 4 days 'early'..
Any tips/stories/advice? Ta.

[catbus]

Oh yes, forgot to say I am cramping and aching like AF is on the way, but again I have had this before with positive results! Maybe I am just trying to convince myself?!! This is a case of 'if it happened again it'd be great, if it didn't, oh well..'

[Muser]

You're not meant to read the result after 10 minutes because it can show you a false positive as it picks up normal hormone levels that everyone (even men) have. So throw your test away and don't torment yourself!