Blood Urea Nitrogen
Test Code
BUN
Description
Urea Nitrogen (BUN) - Urea is the principle waste product of protein catabolism. BUN is most commonly measured in the diagnosis and treatment of certain renal and metabolic diseases. Increased BUN concentration may result from increased production of urea due to (1) diet or excessive destruction of cellular proteins as occurs in massive infection and fevers, (2) reduced renal perfusion resulting from dehydration or heart failure, (3) nearly all types of kidney disease, and (4) mechanical obstruction to urine excretion such as is caused by stones, tumors, infection, or stricture. Decreased urea levels are less frequent and occur primarily in advanced liver disease and in overhydration.
Collect
Plain red top or SST tube.
Preferred volume: 1 mL serum
Pediatric Collection
Minimum volume: 1 mL serum
Storage Transport Temp
Onsite [NJH]: Transport to lab within 1 hour.
Offsite: Separate serum from cells within 2 hours by centrifuge and aliquot into a labeled polypropylene or similar plastic tube. Frozen. Send serum Priority Overnight via FedEx and in a well insulated container on dry ice.
Stability
Stability after cell separation:
8 hours at room temperature
24 hours refrigerated at 2-8°C
>24 hours frozen at -20°C
Performed
Monday - Friday
Methodology
Urease Enzymatic
Turnaround Time
4 hour routine, 1 hour STAT
Department
Core Lab
Synonyms
Urease Enzymatic (Urea Nitrogen, Serum), BUNX
Study Offerings
Not offered
Reference Interval
Newborn - 5 years: 5 - 22 mg/dL
6 - 15 years: 7 - 22 mg/dL
16+ years: 8 - 22 mg/dL
CPT Code
84520
New York Approved
FDA Approved or Cleared
FDA
Approved or Cleared