Alprazolam is a benzodiazepine not an opiate. From the little bit of researching I have done benzodiazepines do not usually  cause what are called "false positives" on drug tests for opiates. There are however a number of drugs and health conditions that may yield such a result. Check out this link and look under the False Positives section to see if you are ingesting any of these substances or have any of these health conditions.

Rick Wirtz

Rick Wirtz is a Psychologist, not a Psychiatrist. Although the majority of Psychologists are not authorized to prescribe medications or give you specific advice about them, they typically have experience working with patients who take a variety of medications. The response above is not intended to diagnose or treat any medical or mental disorder. Any information given in a post about medication is for educational purposes only and primarily to aid you in having an informed discussion with your own physician.