Blood Urea Nitrogen (BUN)
Urea, BUN
Testing Information
Sample Type
Serum
Test Codes
630440
CPT Code
84520
Testing Area
Core Lab - Chemistry
Test Methodology
Abbott Alinity - Enzymatic Urease
Reference Range
0-11 months: 3-20 mg/dL12 months-10 years: 8-22 mg/dL11 years-18 years: 7-21 mg/dL>18 years: 7-25 mg/dLCritical Value: >100 mg/dL
Expected Turnaround Time
Results Available 24 hours from Receipt
Specimen Collection Criteria
Collect one gold top SST tube (minimum whole blood: 4 mL). Let specimen clot for 30-60 minutes and then centrifuge to separate serum from cells. Refrigerate after centrifugation.
Rejection Criteria
Grossly hemolyzed specimens, quantity not sufficient, improperly labeled
Specimen Validity and Retention
Centrifuged SST Tubes:Room Temperature (20-25°C): 4 hoursRefrigerated (2-8°C): 7 daysFrozen (-20°C or greater): UnacceptableSerum Aliquots:Room Temperature (20-25°C): 4 hoursRefrigerated (2-8°C): 7 daysFrozen (-20°C or greater): 7 daysSpecimens retained for 7 days after testing
Courier Transportation
Transport centrifuged tube refrigerated (2-8°C)
Clinical Utility
BUN tests are typically used as an assessment of renal function.
