i just got an email back from my doc. it seems it is the anti-D that i tested positive for after all. this can be caused by blood transfusion, miscarriage, birth, etc. but you can also test positive for it after the rhogam shot.
i had a rhogam shot in january when i was having the spotting... and it usually lasts about 12 weeks. the last 2 blood tests that i've had show that the levels are decreasing. according to the doc this lends itself to the possibility that i'm only testing positive due to the shot i received. i'll continue to have blood work monitoring the levels of anti-D in my system until they are at 0.
really, i'm already giving a pint every time i go in, i'm not too worried about one additional test at this point. right?