Urea Nitrogen
Label Mnemonic: BUN
Epic Lab Code: LAB140
Downtime Form: A-1a General Laboratory Requisition
Chemistry
6240 RCP
356-3527
Specimen(s):
Plasma
Collection Medium:
Plasma Separator Tube 4.5 mL
Alternate Collection Media:
Call laboratory for additional acceptable specimen collection containers.
Minimum:
3 mL whole blood in light green top tube or ONE Microtainer® for pediatric patients.
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
10-20 mg/dL
Comments:
Refer to BD Microtainer® Tubes product sheet for detailed sample collection instructions.

This test is also performed in the Iowa River Landing (IRL) clinical laboratory (for specimens drawn at that site).
Test Limitations:
Criterion: Recovery within plus or minus 10% of initial values. Plasma Icterus: No significant interference up to an I index of 60 (approximate conjugated and unconjugated bilirubin concentration: 60 mg/dL). Hemolysis: No significant interference up to an H index of 1000 (approximate hemoglobin concentration: 1000 mg/dL) Lipemia (Intralipid): No significant interference up to an L index of 1000. There is poor correlation between turbidity and triglycerides concentration. Great care must be taken to prevent ammonia contamination of the specimens to be analyzed for urea/urea nitrogen.
Methodology:
Enzymatic
CPT Code:
84520
 
See also:
Urea Nitrogen-Other, Body Fluid