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HelpTest Code LAB140 BUN
Clinical System Name
BUN
Synonyms
LAB140
BUN
Blood Urea Nitrogen
Sample Requirements
Specimen: Whole Blood
Container(s): Lt. Green/Mint Top Lithium Heparin, Lt. Green/Lithium Heparin Microtainer, Gold SST, Gold Microtainer, Dark Green/Sodium Heparin, Red
Preferred Vol: 1 mL
Minimum Vol: 0.5 mL
Note: Method is affected by gross hemolysis. Not affected by icterus, lipemia, or heparin.
Processing Instructions
Reject due to: Gross hemolysis, age of specimen
Spin: Y
Aliquot: Y
Storage location: Core 5 Chemistry Refrigerator
Off-site collection: Avoid hemolysis. Specimen should be centrifuged within 2 hours of collection. Spin blood and transfer serum or plasma to plastic tube and refrigerate or freeze.
Stability
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum or Plasma | RT |
≤ 24 h |
| Serum or Plasma | 2-8 C |
≤ 5 d |
| Serum or Plasma | -20 C or -70 C |
≤ 180 d |
Availability
| STAT | Performed | TAT |
|---|---|---|
| Y | 24/7 | 1 h |
Performing Laboratory
Seattle Children's Laboratory
Department
Department: Core Chemistry
Phone Number: 206-987-2617 (Client Services)
CPT Codes
84520
Methodology
Method: Colorimetric by Vitros 4600
Analytical Volume: 0.02 mL + 0.03 mL dead space
Limitations:
Reference Range
All Ages: 6 - 20 mg/dL
Description
A high serum urea nitrogen occurs in glomerulonephritis, shock, urinary tract obstruction, pyelonephritis, severe congestive heart failure, hyperalimentation, diabetic ketoacidosis, dehydration, bleeding from the gastrointestinal tract, and other causes of acute and chronic renal failure. Low urea nitrogen often occurs in normal pregnancy, with decreased protein intake, in acute liver failure, and with intravenous fluid administration.
Critical Values
≥ 100 mg/dL