Urea Nitrogen, Serum or Plasma
Also known as: BUN
Use
The Urea Nitrogen, Serum or Plasma test, commonly referred to as Blood Urea Nitrogen (BUN), is a screening test used to evaluate kidney function. Elevated levels of urea nitrogen in the blood can indicate impaired kidney function or kidney disease. It is a standard component of basic metabolic panels and is used to help diagnose and monitor conditions that affect kidney function, as well as to assess the effectiveness of dialysis treatment.
Special Instructions
Specimen should be collected in a plasma separator tube or serum separator tube. Allow the specimen to clot completely at room temperature before separating serum or plasma from cells as soon as possible, but within 2 hours of collection. Transfer 1 mL of serum or plasma to an ARUP Standard Transport Tube, with a minimum required volume of 0.2 mL.
Limitations
The Urea Nitrogen test may have limitations in specificity as elevated BUN levels can occur due to non-renal factors such as high protein diet, gastrointestinal bleeding, dehydration, and increased protein catabolism. Conditions that lower urea production, such as liver disease, may result in lower BUN levels despite normal renal function. Sodium fluoride in specimens can interfere with the test, making it necessary to avoid such additives. Hemolysis, lipemia, and icterus may also impact results and should be avoided where possible.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 3094-0
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.2 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Collect in plasma separator tube. Allow to clot at room temperature, separate serum or plasma from cells as soon as possible, within 2 hours of collection.
Storage Instructions
Refrigerated storage is required for transport.
Causes for Rejection
Specimens containing sodium fluoride will be rejected.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 1 week |
| Refrigerated | 1 week |
| Frozen | 1 year |