The normal ranges for a serum creatinine test are 0.7 to 1.3 milligrams per deciliter of blood for men and 0.6 to 1.1 mg/dL for women, while an optimal range for a blood urea nitrogen, or BUN test, is between 6 to mg/dL of blood. Blood samples for both tests are generally obtained through an intravenous injection, states Healthline.
A serum creatinine test measures the level of blood creatinine, which is a metabolic waste product due to muscular activity. An accumulation of creatinine in the blood is indicative of a renal problem.
A BUN test examines the concentration of urea nitrogen in the blood. This waste material, normally excreted in the form of urine, is produced from protein metabolism. However, aside from a kidney disease, other factors may cause abnormally high readings of BUN tests, notes Healthline.