You can put a little bit of the mixed HCG on a pregnancy test to see if it's legit. Won't tell you about dosing though. Blood test won't work. HCG is a LH analogue, not LH.
Best test is to reach down and grab your nuts. If they haven't shrunk it's all good.
ETA: LH analogue means it's close enough to trick your nuts into thinking it's LH, but it isn't close enough to trick a blood test.