Urea Nitrogen (BUN)

Test Code

38468

CPT Codes
84520<br>Limited Access Code

Includes

For Urea Nitrogen (BUN), Postdialysis Serum, the recommended code is 3292, Urea Nitrogen (BUN), Serum

Preferred Specimen

1 mL plasma collected in a plasma separator tube

Minimum Volume

0.5 mL

Instructions

Centrifuge plasma specimens within 1 hour of collection, transfer plasma to a sterile, plastic, screw-capped vial(s), and ship at room temperature

Transport Container

Sterile, plastic screw-cap vial

Transport Temperature

Room temperature

Specimen Stability

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

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

Unspun plasma separator tube; Unspun green-top tube (heparinized plasma not separated from cells); Anticoagulants other than lithium heparin, sodium heparin or fluoride/oxalate

Methodology
Spectrophotometric

Setup Schedule

Set up: Daily; Report available: 1-2 days

Reference Range

Age	Males (mg/dL)	Females (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 occurs 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.