blood urea nitrogen (redirected from Urine urea nitrogen)

blood urea nitrogen

n. Abbr. BUN

Nitrogen in the form of urea in the blood or serum, used as a indicator of kidney function.

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Blood urea nitrogen (BUN)

A waste product that is formed in the liver and collects in the bloodstream; patients with kidney failure have high BUN levels.

Mentioned in: Acute Kidney Failure, Goodpasture's Syndrome, Kidney Function Tests

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blood urea nitrogen (BUN)

Etymology: AS, blod + Gk, ouron, urine, nitron, soda, genein, to produce

a measure of the amount of urea in the blood. Urea forms in the liver as the end product of protein metabolism, circulates in the blood, and is excreted through the kidney in urine. The BUN, determined by a blood test, is directly related to the metabolic function of the liver and the excretory function of the kidney. Normal findings (in mg/dL) are 10 to 20 for adults, 5 to 18 for children and infants, 3 to 12 for newborns, and 21 to 40 for cord blood. In the elderly, the BUN may be slightly higher than the normal adult range. A critical value of 100 mg/dL indicates serious impairment of renal function. Also called urea nitrogen, serum urea nitrogen. See also azotemia. Compare creatinine.

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blood urea nitrogen (BUN),

n the nitrogen in the form of urea in whole blood or serum. Its concentration is a gross measure of renal function. The upper limit of the normal range is 25 mg/100 ml.

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blood urea nitrogen

BUN Nephrology A metabolic byproduct from the breakdown of blood, muscle and protein which is a measure of the urea level in blood; ↑ BUN often indicates early kidney damage, as well as dehydration, CHF, GI bleeding, starvation, shock or urinary tract obstruction–by tumor or prostate gland; ↓ BUN may indicate liver disease, malnutrition or a low protein diet