Is it possible to get a false positive on an OPK?

Question

AF ended on Monday. I took my 1st opk today at 1pm & it was positive & I'm only cd 8. I retested again around 5:30 & it was negative. I started taking vitex on Monday as well. Is it possible that this made me O early or could it be a false positive?

Answer

I wouldn't consider it positive either, the test line needs to be much darker.

Answer

I wouldn't consider that a positive, I'd wait for the control line to be darker.