Urea Nitrogen

Label Mnemonic:	BUN
Epic code:	LAB140
Order form:	Laboratory Requisition
Supply order:	Supply Order Form
Billing:	Billing Policies
CPT code:	84520

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.

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

Sample Processing:

Centrifuge at a speed and time necessary to get barrier separation of plasma/serum and cells within 1 hour of collection. Send specimen in original tube. Do Not transfer to another tube.
Each sample must be labeled with at least TWO full patient identifiers (First/Last Name & DOB are sufficient for non-UIHC affiliated clients) to avoid sample rejection/delays.

Sample Storage:

Refrigerate.
All sample storage requirements are intended for delivery to UIHC within 24 hours of collection for testing. If samples won't arrive in this time period, please call the UIHC Core Lab for alternative storage/shipping instructions (319-356-3527).

Transport Instructions:

Place labeled specimen into zip-lock type biohazard bag; seal bag.
Place completed requisition into outside pocket of bag.
Transport in cooler with refrigerated coolant packs.

CPT Code:

84520

See also:
Urea Nitrogen-Other, Body Fluid