Urea is a nitrogen-containing substance normally cleared from the blood by the kidney into the urine. Diseases that compromise the function of the kidney often lead to increased blood levels of urea, as measured by the blood urea nitrogen (BUN) test.

Urine urea nitrogen is a test that measures the amount of urea in the urine. Urea nitrogen is a waste product resulting from the breakdown of protein in the body. After the body breaks down the protein from the foods you eat, urea nitrogen is produced (a waste product). If elevated, reduced kidney function is suspected.

  • Normal BUN range: 7 to 20mg/dl.

  • To check if your kidneys are working properly, there are several kidney function tests that may be used in clinical practice. Among all the types, blood tests are often used as a routine test.

    What abnormal results mean

    Higher-than-normal levels may be due to:

    • Congestive heart failure
    • Excessive protein levels in the gastrointestinal tract
    • Gastrointestinal bleeding
    • Hypovolemia (dehydration)
    • Heart attack
    • Kidney disease
    • Kidney failure

    Lower-than-normal levels may be due to:

    • Liver failure
    • Low protein diet
    • Malnutrition
    • Overhydration