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Bun (Blood Urea Nitrogen)

Test Code
BUN


CPT Codes
84520

Preferred Specimen

Serum (gold top) tube



Minimum Volume
0.5 mL


Other Acceptable Specimens
Lithium Heparin Plasma (green top) tube


Instructions

This test is for Urea Nitrogen measurement on Plasma or Serum.  For Urea Nitrogen measurement on Urine, order URUN.  For Urea Nitrogen Clearance, order URCLEAR.  For Urea Nitrogen measurement on Body Fluids, order MISUN.



Transport Container

Serum (gold top) tube or Lithium Heparin Plasma (green top) tube



Transport Temperature
Room Temperature or Refrigeration


Specimen Stability
Room Temperature - 1 day; Refrigerated - 5 days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Quantity Not Sufficient, EDTA (purple top tube) contamination, specimen drawn above an IV


Methodology
Colorimetric

Setup Schedule

Daily upon receipt



Report Available
Upon completion of analysis


Limitations
Ammonium ions may cause an increase in measured BUN/UREA value equivalent to the specimen’s nitrogen content.


Reference Range

Female: 7 - 17 mg/dL
Male:     9 - 20 mg/dL



Clinical Significance

The major pathway of nitrogen excretion is in the form of urea that is synthesized in the liver, released into the blood, and cleared by the kidneys. A high serum urea nitrogen occurs in glomerulonephritis, shock, urinary tract obstruction, pyelonephritis, and other causes of acute and chronic renal failure. Severe congestive heart failure, hyperalimentation, diabetic ketoacidosis, dehydration, and bleeding from the gastrointestinal tract elevate urea nitrogen. Low urea nitrogen often occurs in normal pregnancy, with decreased protein intake, in acute liver failure, and with intravenous fluid administration.

This test is for Urea Nitrogen measurement on Plasma or Serum.  For Urea Nitrogen measurement on Urine, order URUN.  For Urea Nitrogen Clearance, order URCLEAR.  For Urea Nitrogen measurement on Body Fluids, order MISUN.





The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.