BUN

Alternative names:

blood urea nitrogen

Normal values:

7 to 20 mg/dl

What abnormal results mean:

Greater-than-normal levels may indicate:

• congestive heart failure
• excessive protein catabolism (for example, starvation)
• excessive protein ingestion
• gastrointestinal bleeding
• hypovolemia (for example, burns and dehydration)
• myocardial infarction
• renal disease (for example, glomerulonephritis, pyelonephritis, and acute tubular necrosis)
• renal failure
• shock
• urinary tract obstruction (for example, tumor, stones, and prostatic hypertrophy)

Lower-than-normal levels may indicate:

• liver failure
• low protein diet
• malnutrition
• over hydration

Additional conditions under which the test may be performed:

• acute nephritic syndrome
• alport syndrome
• atheroembolic renal disease
• chronic renal failure
• complicated UTI (pyelonephritis)
• dementia due to metabolic causes
• diabetic nephropathy/sclerosis
• digitalis toxicity
• end-stage renal disease
• epilepsy
• generalized tonic-clonic seizure
• Goodpasture's syndrome
• hemolytic-uremic syndrome (HUS)
• hepatorenal syndrome
• IgM mesangial proliferative glomerulonephritis
• interstitial nephritis
• lupus nephritis
• malignant hypertension (arteriolar nephrosclerosis)
• medullary cystic disease
• membranoproliferative GN I
• membranoproliferative GN II
• noninsulin-dependent diabetes mellitus (NIDDM)
• prerenal azotemia
• primary amyloid
• rapidly progressive (crescentic) glomerulonephritis
• secondary systemic amyloid
• Wilms' tumor