Urea Nitrogen (BUN)

Test Code

294X

CPT Codes
84520

Preferred Specimen

1 mL serum collected in a serum separator tube (SST)

Minimum Volume

0.5 mL

Other Acceptable Specimens

Plasma collected in: Sodium heparin (green-top) tube, or lithium heparin (green-top) tube

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 7 days
Refrigerated: 5 days
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Anticoagulants other than heparin

Methodology
Spectrophotometry (SP)

Setup Schedule

Set up: Daily; Report available: Next day

Reference Range

	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

Clinical Significance

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.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.