When can I do an HPT?

I use Gonal-F and Ovidrel injections to ovulate. I usually get a period at about 11 dpo or 12 dpo. When is the earliest I can use an HPT and get a positive result? I have a "feeling" that I am pregnant (waking up to pee in middle of the night which I normally don't do, light lower abdominal cramping which I don't get before or during period, etc.). Today is 10dpo. When can I test?