OPK has a totally blank screen

[MrsWarby]

So, I went and bought clear blue OPK today. I've tested 3 strips--all three of them stayed exactly the same. No surge line or reference line. Completely blank. Does this just mean I'm not ovulating? I find it bizarre that not one of the three strips showed lines.

 

[LuLu15]

What CD are you? And did you hold your urine for 4 hours without drinking anything? Dilute urine can cause there to be no line and you might not be ovulating yet.

 

[MrsWarby]

Hm, I'm CD 28 today. I do drink a lot of water when I test so I should probably not drink anything. Haha good to know!