Sign in →

Test Code LAB6511 Urea Nitrogen, Urine, Timed

Performing Laboratory

Barnes-Jewish Hospital Laboratory

Methodology

Enzymatic (Urease)

Literature Reference:

Package insert: Urea/BUN UREAL reagent. Roche Corporation, 01/2016.

Specimen Requirements

Specimen Type: Urine, timed

Container/Tube: Plain, brown urine container

Specimen Volume: Entire collection

 

Collection Instructions: No additive. Refrigerate specimen during collection.

Additional Information:

1. Starting and ending times of collection are required.

2. See Urine Collection information under General Information.

3. Containers with preservatives are NOT acceptable.

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

Test Classification and CPT Coding

81050-Volume measurement for timed collection

84540-Urea nitrogen

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:

Rifai N, Horvath AR, Wittwer AT eds: Textbook of Clinical Chemistry and Molecular Diagnostics 6 th ed: Chapter 32, p. 479, Elsevier, St. Louis, MO 2018.

Specimen Transport Temperature

Ambient

Additional Information

For BJH Laboratory Use Only

Analyte Stability:

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. Record volume, period, and pH on request form. 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.

Special Instructions

See Urine Collection information under General Information.

See Analyte Stability Chart under General Information for a complete list.