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Test Code 1556 Urea Nitrogen, Urine, Random

Performing Laboratory

Barnes-Jewish Hospital Laboratory


Enzymatic (Urease)

Literature Reference:

Package insert: Urea/BUN UREAL reagent. Roche Corporation, 03/2014.

Specimen Requirements

Specimen Type: Urine, random
Container/Tube: Urine Complete Cup Kit
Specimen Volume: 10 mL

Collection Instructions: No additive.
Additional Information: See Urine Collection in Special Instructions for additional information.

Day(s) Test Set Up

Monday through Sunday
Turnaround Time:
STAT: 1 hour after receipt in laboratory
Routine: 2 to 4 hours after receipt in laboratory

Reference Values

No established reference intervals

Note: Calculation of nitrogen balance requires knowledge of 24-hour urea nitrogen and daily protein intake. Use the following formula: nitrogen balance=daily protein intake (g)/6.25-(24 hour urine urea nitrogen+3 or 4*).
*Use 4 if diarrhea is present.

Literature Reference:

Tietz, Burtis CA, Ashwood ER, Bruns DE eds: Textbook of Clinical Chemistry and Molecular Diagnostics 5th ed: Chapter 25, p. 669, Elsevier, St. Louis, MO 2012.

Test Classification and CPT Coding


Additional Information

For BJH Laboratory Use Only

Analyte Stability:

See Analyte Stability Chart in Special Instructions.

Specimen must be kept refrigerated during collection and before delivery to limit bacterial growth.

Laboratory Processing Instructions:

Test performed in BJH Core Lab. Mix urine well. Using 13x100 test tubes, prepare a 7-mL aliquot and deliver to the automated line for centrifugation and delivery to Cobas 8000 for analysis. Completed specimen is stored refrigerated for 5 days.

Specimen Transport Temperature


LOINC Code Information

Name LOINC Code
Urea Nitrogen in urine 3095-7