The blood urea nitrogen or BUN is a blood test that measures the amount of urea nitrogen in the bloodstream. It reflects how well your kidneys are. When a person is dehydrated, false results might be obtained as BUN levels increase when blood is concentrated. Elevated BUN levels indicate dehydration, excessive protein intake and impaired renal function. Low BUN levels indicate over hydration, liver damage and malnutrition.
Creatinine is a waste product produced by muscle metabolism. Kidneys filter creatinine to be excreted through the urine and the renal function is reflected. Elevated levels indicate renal impairment. The opposite happens for urinary creatinine clearance; during renal impairment, urinary creatinine is extremely low. Measuring urinary creatinine clearance during unilateral kidney impairment is insignificant as the healthy kidney can still excrete creatinine through the urine.
Blood glucose levels can rise well above normal for significant periods without producing any permanent effects or symptoms. However, chronic hyperglycemia at levels more than slightly above normal can produce a very wide variety of serious complications over a period of years, including kidney damage, neurological damage, cardiovascular damage, damage to the retina or damage to feet and legs. Diabetic neuropathy may be a result of long-term hyperglycemia.