3 days of opk kits the bottom on is 3 day ago middle is yesterday (positive) the top one is today about 5 min ago. Think it werid that I only got one positive isn't it supposed to be a few days let alone that in all the months I've been try and using opk I have never had a positive test or a line dark. So fingers crossed for my rainbow baby just hoping to get some reasurerns my husband "don't think they work"