I have read several places that there is no way for a drug test to detect the difference between on Oxymorphone (OPANA ER) and an Oxycontin on a drug test. Is this true? My husband ran out of his pain Meds (Opana) and took a couple Oxycontin instead but his pain Management doctor does random drug screens. We are worried that he may not pass but then I read an article that said they both break down in your system to the oint that you cant distinquish between the two. Anyone out there know for sure?