How do OPKs work? user banned
4th Jun '13

I know that theres always 2 lines but do they get darker or stay faint and then one day BAM positive?

Amelia [a Mom] 1 child; 4 angel babies; Tallahassee, Florida 17360 posts
status 4th Jun '13

Pretty much! Sometimes you will see it start to get darker the day before but it goes from faint to positive pretty much overnight.

Chynee 2 kids; 2 angel babies; New York 767 posts
4th Jun '13

Sounds like you already kno to me. Lol. Thts pretty nuch how it goes

CCasto Due July 6; TTC since May 2013; 1 child; El Paso, Texas 1669 posts
5th Jun '13

I think it may depend on what you buy. I have some urine strips and unless both lines are the same color it is negative. I just started using them a week ago (I had my Mirena removed in May) but AF arrived Sunday afternoon. I am now going to start checking around day 10 until I have a positive or AF arrives.