Thank you for your question and welcome to AnxietyConnection.com.
If you have a prescription for Xanax, you should be able to bring the prescription with you to the testing center and this medication should not be included in the results.
According to the website homedrugtestingkit.com, this type of medication can stay in your system anywhere from 2 days to 10 days. There is no exact answer as people metabolize medication at different rates.
I hope this helps
Eileen