Changing / Increasing ADHD Meds

AD just turned 9. She has been on Adderall XR for about 3 years. She was originally on 5 mg, then changed to 10mg and has been stable on that for about 2.5 years. She was started on meds when she was in FC. She has anxiety too, although she has never been diagnosed, and that seems to have calmed down since the adoption. AD is a very bright girl. She has been in the gifted program at school and enjoys it. She has to be tested for it this year to remain in the program. The first time, she bombed the testing because she was having emotional problems between Christmas and her birthday (always a tough time for her, she misses her birthmom) and no one told us about the testing. Now we are getting close to state testing. Her teacher is saying that she is not focused on her assessment tests. I want to make sure that she is doing as well as she can and if we need to increase her meds or change them, I want to make sure we do that. So, I guess what I am asking is how do I know if she needs an increase or change in meds, or if it is just test anxiety? How often do kids on ADHD meds need them changed or adjusted? Thanks!