If your friend has not taken any of the quetiapine her doctor prescribed, she should let her doctor know before she has the blood work done. He is probably looking for the levels of this medication in her bloodstream. It would be a waste of time and money since none will be found.
You COULD call her doctors office and advise them about what your friend is planning to do, but since you are not family, HIPPA laws will probably bring you to a dead end. POSSIBLY. I say it would be worth trying.
Another source of excellent advice would be to call the pharmacist where the medication was dispensed and ask for his/her opinion. They can not tell anyone to start or stop a medication, but they can answer your questions and concerns.
Much will depend on why this medication was prescribed.
I wish you the best.
RubyWitch