OPK test question

Cathy

Hi ladies, I’ve never checked my LH surge after ovulation but this time, for no reason I did this time.

I’m already 3 DPO, when I tested last night and this late morning, the line are still there just not as dark as the control line anymore.

Question is, when will this test line be totally gone or they won’t? They will just be very faint thin line until AF show up?