During a recent urine screen, I tested positive for Phenobarbital, which I have not taken since I was 6 years old (36 years ago). I do take high doses of Fioricet and Fiorinal and have a prescription. The medical review officer is insisting that I took the Phenobarbital. My job is in jeopardy. I know that there is a barbiturate in both the Fiorinal and Fioricet. Could my 20+ year history of using these drugs cause this? They used the GC MS and are certain that I am "guilty". Help. I REALLY want this job, and will not get it if I cannot figure out the problem. It will cost $150 for a reanalysis (which may have been contaminated) or $600 for a new test. One last detail--as I receive the prescriptions I have to undergo monthly drug testing at my primary care provider's office, and have not had a positive test in 3+ years. Any suggestions would be GREATLY appreciated. THANK YOU!