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HelpTest ID: BUN Blood Urea Nitrogen (BUN), Serum
Reporting Name
Bld Urea Nitrog (BUN), SUseful For
Screening test for evaluation of kidney function
Specimen Type
SerumNecessary Information
Patient's age and sex are required.
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
Specimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 365 days |
Reference Values
Males
1-17 years: 7-20 mg/dL
≥18 years: 8-24 mg/dL
Reference values have not been established for patients who are <12 months of age.
Females
1-17 years: 7-20 mg/dL
≥18 years: 6-21 mg/dL
Reference values have not been established for patients who are <12 months of age.
Day(s) Performed
Monday through Sunday
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
84520
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| BUN | Bld Urea Nitrog (BUN), S | 3094-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| BUN | Bld Urea Nitrog (BUN), S | 3094-0 |
Clinical Information
Urea is the final degradation product of protein and amino acid metabolism. In protein catabolism, the proteins are broken down to amino acids and deaminated. The ammonia formed in this process is synthesized to urea in the liver. This is the most important catabolic pathway for eliminating excess nitrogen in the human body.
Increased blood urea nitrogen (BUN) may be due to prerenal causes (cardiac decompensation, water depletion due to decreased intake and excessive loss, increased protein catabolism, and high protein diet), renal causes (acute glomerulonephritis, chronic nephritis, polycystic kidney disease, nephrosclerosis, and tubular necrosis), and postrenal causes (eg, all types of obstruction of the urinary tract, such as stones, enlarged prostate gland, tumors).
The determination of serum BUN currently is the most widely used screening test for the evaluation of kidney function. The test is frequently requested along with the serum creatinine test since simultaneous determination of these 2 compounds appears to aid in the differential diagnosis of prerenal, renal and postrenal hyperuremia.
Clinical Reference
Lamb EJ, Jones GRD: Kidney function tests. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:497-500
Report Available
Same day/1 to 2 daysMethod Name
Photometric/Urease
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
mcl-kidney