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Test Code BUN or LAB140 BUN, Serum or Plasma

Specimen Requirements

Container Type:

Optimal: Gold or Mint*

*For STAT requests

Acceptable: Red or Green

Optimal Collection Volume: 

4.5mL; full tube

Minimum Volume:
  • Adults: 1 mL whole blood
  • Neonates: 1 microtainer (400-600 uL)
Collection Instructions:

Gently invert the sample 5-6 times after collection.

Specimen Transport:

Refrigerate

Processing Instructions: 

1. If serum, allow the specimen to clot for 30 minutes.

2. Centrifuge specimen within 2 hours of collection.

3. After centrifugation, specimen tubes without a gel barrier should have the serum or plasma aliquoted to a false bottom container.

4. Keep the serum or plasma refrigerated until testing can be performed.

Specimen Stability

Specimen Type Temperature Time
Serum* Refrigerated 7 days
Room Temperature 8 hours
Frozen 1 year

*Note: Heparinized plasma in gel separator tubes is less stable than serum and is only suitable for add-on testing up to 2 days following sample collection.

Specimen Rejection Criteria

Hemolysis Mild OK; Moderate OK; Gross Reject
Lipemia Mild OK; Moderate OK; Gross Reject
Icterus Mild OK; Moderate OK; Gross Reject
Other Quantity not sufficient

Useful For

This assay is useful in the evaluation of kidney function.

Methodology

Roche Cobas - Kinetic test with urease and glutamate dehydrogenase

Reference Ranges

Age

Reference Range and Reporting Units

< 1 year 4-19 mg/dL
1-17 years 5-18 mg/dL
18-60 years 6-20 mg/dL
> 60 years 8-23 mg/dL

Day(s) Performed

24/7

Expected TAT

Same day

Performing Laboratory

Bronson Laboratory, Chemistry - Kalamazoo, Battle Creek, Paw Paw, South Haven

Sample Retention Time

7 days

CPT Code

84520

LOINC Code

3094-0