The normal range for serum creatinine is 0.6 to 1.3 milligrams per deciliter, according to Mayo Clinic, so elevated serum creatinine levels would be any values above 1.3. A serum creatinine test measures the level of creatinine in blood, which can indicate how well the kidneys are working.
Creatinine is a chemical waste product of muscle activity, according to the National Kidney Foundation. Normally, the kidneys can remove most creatinine in the blood. When kidneys are not functioning properly, serum creatinine levels rise. Health care providers use the results of serum creatinine tests to calculate glomerular filtration rate, which indicates kidney function.