OPK question

I know how ya'll just love these lol. So are OPK's like HPT's, where after like 10 minutes they are invalid? I swear to god, I should know how to use OPK's since I have been trying since Feb but smurf, a girl can forget lol. I got my light line but then it started to get darker. I should be getting a positive pretty soon. It was lighter this morning and no I didn't use FMU lol.

I am sure it is similar because as they dry they can get darker I would think.

Quoting katxo:" I know how ya'll just love these lol. So are OPK's like HPT's, where after like 10 minutes they are invalid? ... [snip!] ... it started to get darker. I should be getting a positive pretty soon. It was lighter this morning and no I didn't use FMU lol."

mine said can be read for one hour.