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22941 Urea Nitrogen

Urea Nitrogen
Test Code: BUN
Synonyms/Keywords
BUN, Blood Urea Nitrogen​, i-Stat BUN
Useful For
Urea nitrogen measurements are used in the diagnosis and treatment of certain renal and metabolic diseases.​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ ​

Plasma​/Serum

 

 Lithium-heparin Plasma Separator (PST), Serum Separator Tube (SST)​ Lithium or Sodium-heparin Green Top (GTT), Red Top Tube (RTT) 1 mL​ 0.5 mL​ 0.5 mL whole blood​
​i-Stat only = Whole Blood ​Lithium-heparin Green Top Tube (GTT) ​ ​1 mL ​200uL ​
Collection Processing Instructions
Samples collected in a RTT or GTT must be removed from cells within one hour for storage or transport. Samples collected in gel barrier tubes must be removed from the primary tube prior to transporting to Marshfield. Do not send the primary collection tube.
 
Stat orders will be run locally on the i-Stat.  Non-stat orders will be sent to Marshfield for analysis. 
i-Stat:  Sample must be tested within 10 minutes of collection.
Specimen Stability Information
Specimen Type Temperature Time
Plasma/Serum​ Ambient​ 5 days​
Refrigerate​ 7 days​
Frozen​ 3 months​
i-Stat Whole Blood​ ​Ambient ​10 minutes
Rejection Criteria
Specimens in ammonium heparinate or oxalate
i-Stat testing:  clotted samples​
​i-Stat testing: anticoagulants other than lithium heparin
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Chippewa Falls ​​Monday through Friday ​Less than 2 hours​ ​Biochromatic Rate Technique/Siemens Dimension
​Cornell ​​Monday through Friday
1 day (sent to Marshfield)
* stat order on i-Stat run locally = Less than 2 hours​
Urease GLDH Rate Assay/Beckman AU
​Ion-Selective Electrode/i-Stat
Weston
 ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Eau Claire ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Park Falls
 ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Ladysmith Medical Center ​​Monday through Sunday ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Lakeview Medical Center ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 2 hours​ Urease GLDH Rate Assay/Beckman AU
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Neillsville​Monday through Friday​Less than 2 hoursBiochromatic Rate Technique/Siemens Dimension​
​Stevens Point ​​Monday through Friday ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
Wisconsin Rapids​ ​​Monday through Friday ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
Reference Range Information
Performing Location Reference Range
All Performing Sites

0-1 year: 1-14 mg/dL

2 - 17 years: 5-20 mg/dL

>=18 years: 6-24 mg/dL​

See Critical Value Policy for list of current critical values.​​ ​
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84520 ​ ​ ​ ​
Synonyms/Keywords
BUN, Blood Urea Nitrogen​, i-Stat BUN
Ordering Applications
Ordering Application Description
​Centricity

​a. BUN (Blood Urea Nitrogen)

b. Urea Nitrogen-Blood (BUN)

c. BUN

​Cerner ​Blood Urea Nitrogen
​COM ​Urea Nitrogen - Blood (BUN)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ ​

Plasma​/Serum

 

 Lithium-heparin Plasma Separator (PST), Serum Separator Tube (SST)​ Lithium or Sodium-heparin Green Top (GTT), Red Top Tube (RTT) 1 mL​ 0.5 mL​ 0.5 mL whole blood​
​i-Stat only = Whole Blood ​Lithium-heparin Green Top Tube (GTT) ​ ​1 mL ​200uL ​
Collection Processing
Samples collected in a RTT or GTT must be removed from cells within one hour for storage or transport. Samples collected in gel barrier tubes must be removed from the primary tube prior to transporting to Marshfield. Do not send the primary collection tube.
 
Stat orders will be run locally on the i-Stat.  Non-stat orders will be sent to Marshfield for analysis. 
i-Stat:  Sample must be tested within 10 minutes of collection.
Specimen Stability Information
Specimen Type Temperature Time
Plasma/Serum​ Ambient​ 5 days​
Refrigerate​ 7 days​
Frozen​ 3 months​
i-Stat Whole Blood​ ​Ambient ​10 minutes
Rejection Criteria
Specimens in ammonium heparinate or oxalate
i-Stat testing:  clotted samples​
​i-Stat testing: anticoagulants other than lithium heparin
Useful For
Urea nitrogen measurements are used in the diagnosis and treatment of certain renal and metabolic diseases.​
Reference Range Information
Performing Location Reference Range
All Performing Sites

0-1 year: 1-14 mg/dL

2 - 17 years: 5-20 mg/dL

>=18 years: 6-24 mg/dL​

See Critical Value Policy for list of current critical values.​​ ​
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Chippewa Falls ​​Monday through Friday ​Less than 2 hours​ ​Biochromatic Rate Technique/Siemens Dimension
​Cornell ​​Monday through Friday
1 day (sent to Marshfield)
* stat order on i-Stat run locally = Less than 2 hours​
Urease GLDH Rate Assay/Beckman AU
​Ion-Selective Electrode/i-Stat
Weston
 ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Eau Claire ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Park Falls
 ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Ladysmith Medical Center ​​Monday through Sunday ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Lakeview Medical Center ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
Marshfield​ Monday through Sunday​ Less than 2 hours​ Urease GLDH Rate Assay/Beckman AU
​Minocqua ​Monday through Sunday​ ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
​Neillsville​Monday through Friday​Less than 2 hoursBiochromatic Rate Technique/Siemens Dimension​
​Stevens Point ​​Monday through Friday ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
Wisconsin Rapids​ ​​Monday through Friday ​Less than 2 hours​ ​​Biochromatic Rate Technique/Siemens Dimension
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84520 ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.