You can have two lines on an OPK even if you're not ovulating. The 2nd line has to be 'as dark, or darker' than the first to indicate an LH surge (impending ovulation). Good luck to you!
MY hpt's were not showing a positvie even when i was 4 days late...i took a opk and it showed up positive so i went out and bought yet another hpt and it finally showed +
Your HPT would show positive b4 an OPK. I did this, but I only got a positive on an OPK 2 days after I got a positive on a HPT. ( It was neg. the 1st day I got my pos. on my hpt.) OPK's are far less sensitive than a HPT. Good luck.
ovulation tests detect lh and hcg in your system,where's a hpt only detects hcg. so its hard to say unless the final test was a hpt.check out peeonastick.com
has some interesting facts about that,good luck.