A creatinine clearance test measures how well creatinine is removed from your blood by your kidneys. This test gives better information than a blood creatinine test on how well your kidneys are working. The test is done on both a blood sample and on a sample of urine collected over 24 hours.
Therefore, 5 mg of oxycodone is about 16 mg of hydrocodone so oxycodone is about 3 times stronger than hydrocodone. However, geminigirl is right in that everyone is different. I have read that some say hydrocodone works better for their pain than percocet and viceversa. For me, percocet works a lot better for my pain.
There does not appear to be a great deal of difference between oxycodone and hydromorphone. There is however a difference in the equivalent potency when it comes to dosing the drug. In simple terms, this means that the same dose of hydromorphone does not have the same effect as an equivalent dose of oxycodone.