Send the document number and details of the error to the QA Team Leader as that is the correct person who can actually take care of the matter. You can find out who the QA Team Leader for your group is either on the facility's client profile or it's usually among the signature lines on the job report sent out in the morning.
I've actually had good results when I have informed the QA Team Leader a couple times about QA errors, both of which severely affected patient care.