UREA NITROGEN (BUN)

Clinical Significance

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.

Preferred Specimen(s)
1 mL serum

Alternative Specimen(s)
Sodium heparin (green-top) tube • Lithium heparin (green-top) tube

Minimum Volume
0.5 mL

Transport Container
Serum Separator Tube (SST®)

Transport Temperature
Room temperature

Specimen Stability
Serum and plasma
Room temperature: 7 days
Refrigerated: 5 days
Frozen: 28 days
Reject Criteria
Anticoagulants other than heparin

Setup Schedule

Methodology
Spectrophotometry (SP)

Reference Range(s)
     Male
(mg/dL)    Female
(mg/dL)
<1 Month    4-12    3-17
1-11 Months    2-13    4-14
1-3 Years    3-12    3-14
4-19 Years    7-20    7-20
≥20 Years    7-25    7-25

Alternative Name(s)
Blood Urea Nitrogen,BUN