No, OPKs can detect HCG. Please see: http://www.peeonastick.com/opkhpt.html

LH and HCG are almost identical chemically. HCG just has something extra that HPTs detect.

This is important to remember though:
Gabs might want to take that into consideration.

Yeah but if you notice when the OPK shows up positive ,the HPT does too. I always thought that an OPK would show positive before the HPT but Peeonastick showed me otherwise.

Gabby I found this online, hope it helps...sounds promising!!

LH and hCG are, at a molecular level, nearly identical. hCG has a beta subunit, meaning it has an extra little "doodad." To use a stupid but easy to understand example, LH and hCG are identical twins, except that hCG wears a funny hat.

An OPK tests only for the part of the molecule that LH and hCG have in common (the "face" or "body" of the identical twins.) So an OPK will turn positive when it detects either of the "identical twins"-- ovulation or pregnancy hormone.

The reverse is not true, however, because an HPT tests for the part of the molecule that is unique to hCG (the "hat.") Therefore, a pregnancy test will turn positive only in the presence of hCG, whereas an OPK will turn positive in the presence of hCG or LH.

ok girls...listen...opk are used tod detect the hormone LH. HPT are used to detect HCG. But...LH and HCG are almost identical. So on an opk it is able to pick up LH as well as HCG. The thing is that by the time an opk is detecting hcg then a hpt should be able to detect it as well. With my last baby i kept getting postive opks and didnt know what was going on..so i took an hpt and it was positive ...so i was preggo!
You can go to peeonastick.com and it will tell you how opk as hpt works. It is a good sign then you may be preggo..but dont use it as a hpt!

The reason i am testing tonight with a hpt is because im on cd 21 thinking about 9 or 10dpo. I have two very strong dark dark opks today which i dont think im oing. i had o pain , ewcm ,and pos opk last monday...so therefore doubt im oing? SOOOO why the positive opk right? WEll it may be detecting my hcg if i am infact preggo. I am not waiting till the am because if the opk is detecting hcg right now than i would think a hpt would too!..make sense? if it is negative i will do one tomorrow morning and if that is negative..then i am assuming i am going to be oing late? and if its positve then well i will be SOOO happy!

lol i type this..and then read you all found it too! haha thanks girls your great!

Also feeling sick and itchy boobs so feeling alittle hopeful..i dont think i will be too upset if its negative because at least i may be oing now? and still in with a chance?

I thought that was what was going on. Happy for you either way but hope it is a so if the HPT is negative I think you should inform your doctor that you are just now Oing.

Yeah i know...i had my cd21 tests today as well..so i will know either way if i didnt o then and maybe oing now and see what she says?

I saw a post from one woman last week that went in for her CD21 test, they called her with the results and additionally she found out she was preggo!!!

Either way, I think this is win-win. You're either preg or know you need to BD like crazy!

I do have some ewcm right now..maybe it is just O? ...ah who knows so annoying!