If I ovulated in the middle of the day yesterday, would my OPK be negative that night?

Question

I had all the signs & symptoms of ovulation yesterday, CD13, and when I took an OPK that night it was negative. But I swear I ovulated. What does this mean? Is that possible?

Answer 1

A positive result on an OPK test indicates that there is a surge in your LH hormone, which means that ovulation WILL occur in 24-36 hours.  If you already ovulated, the LH surge would have passed already, so you would get a negative result on an OPK test.

Answer 2

OPK's PREDICT ovulation.  It measures the LH hormone surge, which then in 12 to 36 hours later causes the release of the egg.  So, yes, you would probably have a negative OPK after you have ovulated.