well, not really. what you are referring to is the BUN levels
No, urea is the breakdown product of protein, and if the levels are elevated, it is more than likely you eat a high protein diet or you are dehydrated, or you are in one of the stages of renal failure. Your creatinine and potassium will also be high.
Creatinine is the breakdown product of creatine-phosphate, which is a high energy molecule that transfers a phosphate group to ADP to form ATP during anaerobic respiration so your muscles can keep working.
The more muscle you have, the more creatine you have, therefore the more creatinine you have.
Supplemental creatinine also can cross react with the blood test assay.
If you want a more accurate result, google Cockroft-Gault, put in your age, weight, sex and creatinine levels and you will have a far more accurate indicator of renal function.