Can a negatice pregnancy test change to a positive after several hours?

[TheBreastmilksOnMe]

I took a clear blue pregnacy test two days ago and at first glance it looked negative, but in certain lights I though I could make out a barely perceptible line (wishful thinking?) so I put it to one side. The next day I looked at it again and there was a very visible positive line.

Now I am confused as they say to discard the test after 10mins but why would it change to positive over night?

My breasts are so tender they feel as though they are on fire and my DS (who is breastfeeding) has diarheoa. This happened the last time I got pregnant a few months ago but I then miscarried.

I took a First response yesterday which was negative. I'm due on in 5 days time.

Has anyone any understanding of these pregnancy tests?

yes, it's called an evaporation line, sorry.

Yes it can, as it dries out it can leave a 'positive', hence them telling you to discard after 10 minutes.

Don't be disheartened though - with my last pg I had 2 negs before 5 positives :-)

I have had several blue dye tests do this to me.I only trust FR. But I think if you aren't due for 5 days there's still a chance you may well be pregnant, but please don't trust the blue dye test! (Oh, and don't trust the stupid help-line who told me it was due to breastfeeding - there is NO way that breastfeeding can give you a false positive test.)

Last year I had several positives, with the line getting darker like yours did, only to find I was never pregnant.I haven't yet(20 months) had a post partum AF, so it couldn't have even been a chemical.

Blue dye tests are notorious for false positives and a whole lot of disappointment. Check out this thread on another site:
www.mothering.com/discussions/showthread.php?t=1206310

Test again with a pink dye test.

I hope you get the outcome you'd like.

Thanks girls! Thing is I've had an evaporation line after a few days with my first DS and it turned out to be positive. I also got a false negative from a clear blue digital. I'm just not going near a clearblue again. They are rubbish. I'll stick to FR!

CB are rubbish, I have had a lot of false positives from them.

Hope you get the result you are hoping for.

Five days before your period is due is quite early to test so it may well be a false negative from testing too early.

I got a -ve on 9, 10 and 11dpo but +ve on 12dpo which shows I was testing too early...but I just couldn't help myself!

You're right Fanjo- the 2ww is a killer isn't it! I'm only just 10dpo so probably waaaay to early even for a FR. Will just have to keep fingers crossed. I've bought some internet cheapies so just waiting for those to arrive now then I can test away to my hearts content without breaking the bank!