Is there a difference between oxicontin and oxicodone when taking blood drug tests?

I am perscribed Oxicontin 40mg - my friend gave me a couple Oxicodone 30mg because I ran out. My doctor is supposed to drug test me to make sure the Oxycontin is in my system.... Will they show up different or will they show up the same? Please only educated answers from people who KNOW Oxicontin/Codone and other opiate type narcotics. I am pretty sure they will not notice any difference but would like a 2nd 3rd n 5th opinion LOL Thanks!!