What is blood urea nitrogen?
Blood Urea Nitrogen (BUN) is the amount of nitrogenous waste products in blood. The BUN may increase if the fluid volume in the body decreases and this is dangerous since it can lead to an acute kidney injury. In other words, BUN is a measure of the amount of nitrogen in the blood in the form of urea, and a measurement of renal function. Urea is a substance secreted by the liver, and removed from the blood by the kidneys. The BUN value is obtained in the lab results of a blood sample. They take this value and compare it with the value of serum creatinine which is also measured from blood. The comparision is done via ratio. The ratio helps identify the CAUSE of the acute renal injury. If the ratio equals to 10-20:1 then either the kidney is normal or a POST renal cause is involved, such as urethral obstruction or any form of obstruction outside the kidney. If the ratio is more than 20:1 then the cause is PRE renal, such as a shock or a sudden drop in blood pressure. If the ratio is less
