OPK as HPT

So I have been TTC for 2 years now and according to my first positive o test I ovulated last Tuesday. I had all my typical o symptoms as well. Well today just for the heck of it I took another o test thinking it would be negative. Well it was BFP! Test line darker than control line. Has anyone else heard that theory that an o test can pick up on HCG as well as lh? Anyone wanna test it out and let me know. Here's a pic of my o tests for the last week.