If a person has only taken oxycodone 15 mg for one week how long will it take to get out of his system for a urine test? he only took it one time a day for pain in his knees and elbow.

Can check yourself.: Usually 1-3 days is enough time off the drug to clear the system. This depends on multiple factors though. A person can check at home. See http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/InVitroDiagnostics/DrugsofAbuseTests/ucm125722.htm See http://www.mayomedicallaboratories.com/test-info/drug-book/opiates.html