I take vicodin every day for hip pain my dr did a drug screen on me today (without me knowing) and it came back neg how is that possible?

A lot of variables: Urine drug screens depend upon alot of different variables. How often you are taking the medication. When the last dose of the medication was prior to the test. The dose of the medication. How fast your body metabolizes the medication. What type of test was used, a screening assay or a gc/ms confirmation test. What the lower limit cut of the medication the lab uses can all alter a test.

Not possible: Routine drug screen should pick up the vicoden unless they are not looking for vicoden. ! maybe you can answer the question yourself?

Low dose?: Some basic drug screening tests do no detect small doses of this medication. If you are positive you took the medication that is the only way this could happen. A quantitative test done at a specialty lab would be accurate even at small doses. Most commonly people are not taking it.