what is bun in your blood test
BUN (blood urea nitrogen) is a blood test to check kidney function. So is the serum creatinine test. When your doctor talks about BUN/creatinine levels or a BUN-to-creatinine ratio, he or she is referring to the two main blood tests that tell how well the kidneys are filtering waste products from your blood. The ratio of BUN to creatinine is normally in the range of 10:1 to 20:1.